DFI NF4 Ultra-D vdimm mod: come inside.

[Malves]

Posted at www.hardwareasylum.com. Here's the thread (http://www.hardwareasylum.com/forums/showthread.php?t=119). Have fun!:)

[mcnbns]

Details? Why is this better than just changing it through the BIOS? Thanks! :)

[Malves]

Just giving ppl another way to up vdimm using 3.3v rail. It's just the old and trustworthy vdimm mod. With a modded PSU, you can get stable vdimm over the default in BIOS when using 3.3v rail.

There is the jumper trick to make more options available in the BIOS. But what if you forget about that and select a vdimm that's higher than your rail? You can kiss your board goodbye
You can setup the board to use 5v rail, but you get a hot FET that just brings instability.
A few members reported having issues when using the 5v rail. User or not user error, I don't care. Here's the mod and I hope it helps ppl out there.

IMO, the vdimm mod using 3.3v rail will give you cleaner voltage.

[persivore]

Good work on the Vmod bro :toast:

Malves and myself have been thinking, this mod could possibly help people who are experiencing cold boot problems. The problem with cold boots has been found to be the fact that the board feeds the RAM with ~2.6v before the BIOS is loaded. By doing this mod, it should be possible to set the Vdimm that the board boots with, using the variable resistor, so that the voltage the Vdimm regulator gives out is set by the user, and not what the BIOS is being told to give out. You will need to set the voltage in BIOS to the minimum possible (so that the voltage doesn't suddenly rise when the BIOS is loaded), and use the variable resistor to raise the voltage to the required level.

Does anyone want to test this theory?

[stealth17]

Good work on the Vmod bro :toast:

Malves and myself have been thinking, this mod could possibly help people who are experiencing cold boot problems. The problem with cold boots has been found to be the fact that the board feeds the RAM with ~2.6v before the BIOS is loaded. By doing this mod, it should be possible to set the Vdimm that the board boots with, using the variable resistor, so that the voltage the Vdimm regulator gives out is set by the user, and not what the BIOS is being told to give out. You will need to set the voltage in BIOS to the minimum possible (so that the voltage doesn't suddenly rise when the BIOS is loaded), and use the variable resistor to raise the voltage to the required level.

Does anyone want to test this theory?

lmfao

http://www.xtremesystems.org/forums/showthread.php?p=916293#post916293

i still say the utt-ch just sucks for high voltage long-term

[timpanogos]

Please elaborate on this vdimm modification..

1. say you only have 3.3 volts on your 3.3 volt line. This mod will allow you to get up to say – 4.0 volts from that 3.3 source?

2. I just did a sense line mod to my 3.3 I set it to 3.5, and have bios set at 3.3 – this actually gives me a DMM measured 3.38 on the memory. Are you saying that if I set my bios to say 3.6, with only 3.5 set on my 3.3 line, this would fry mobo components? Seems this would simply peak out at 3.5, no matter what you set the bios to above that? Note, that setting it to 3.4 may exceed that actual 3.5 volts that are currently set (i.e. .08 higher than 3.3 setting).

[mcnbns]

Just giving ppl another way to up vdimm using 3.3v rail. It's just the old and trustworthy vdimm mod. With a modded PSU, you can get stable vdimm over the default in BIOS when using 3.3v rail.

There is the jumper trick to make more options available in the BIOS. But what if you forget about that and select a vdimm that's higher than your rail? You can kiss your board goodbye
You can setup the board to use 5v rail, but you get a hot FET that just brings instability.
A few members reported having issues when using the 5v rail. User or not user error, I don't care. Here's the mod and I hope it helps ppl out there.

IMO, the vdimm mod using 3.3v rail will give you cleaner voltage.
Sounds good. :)

I'm going to stick with the 5V jumper method, but I'm glad someone gave people who want really stable VDIMM a mod, finally. :toast:

[Malves]

Please elaborate on this vdimm modification.

1. No.

2. I read it would damage the board.

[timpanogos]

wow, thanks for the safety tip there Malves! I'll be sure and watch that closely if I ever go to set my bios to 3.4. Any idea what a "safe" rail voltage would be above your current/desired vdimm?

p.s.

Also wondering then, if one did have like say 3.7 volts on the rail, and wanted to run at say 3.5 vdimm, with the mobo mod, you may want to set your bios to say 3.6 and then adjust the mod's pot for the desired 3.5 exact?

Like even now, the overvolting of my rail seems to cause .08 volts more than the bios setting of 3.3 to actually be applied. Your mod would/could limit this further to the exact 3.3 -- is this right?

The above assumes the bios controls that chip you are further moding.

[Malves]

No, you always select less than the value you want, and then trim to it.

Yes, with a vdimm mod you have total control over the voltage.

[timpanogos]

No, you always select less than the value you want, and then trim to it.

but ... that is what you read could blow the board right ?? (rail less than bios setting) .. For example, say I want 3.4 volts .. so safety says, set your rail to 3.3, set your bios to 3.4 and then tweak the rail until you have 3.4 on your memory.

Sorry for all the bother, just saw your name on the hellfire sense mod thread (and ensuing mess) .. and know by that read, that you know what the heck is up.

Thanks!!

Chad

[felinusz]

Malves, will this mod work when on the 5V VDIMM jumper?


I would use this in tandem with the 5V jumper, to fine-tune VDIMM.

As it is, my board overvolts VDIMM by ~0.8V-0.9V, so 3.78V and 3.89V are the only two higher VDIMM selections I can make. I want to test between 3.8-3.85V :p

[Malves]

I didn't test it with 5v rail. I'll do that tomorrow and let you know.:)

[dippyskoodlez]

I didn't test it with 5v rail. I'll do that tomorrow and let you know.:)

so if your 3.3v line is at 3.6, you can select up to 3.5?

[Malves]

Trying to find where I read about board being damaged if selecting vdimm in BIOS > 3.3v rail. Can't find it, thou.:(

Please, you guys have to understand this vdimm mod works just like any other vdimm mod for boards that use a 3.3v rail for RAM. All you have to do is to use the board set at 3.3v and a modded PSU. Just like we used to do.:)

You can use the jumper trick posted in the AMD section with a modded psu. But a vdimm mod will give you total control over voltage adjustments.

Tomorrow I'll be checking the mod with the 5v rail to see if vdimm over 4v is possible for the kamikazes (http://www.xtremesystems.org/forums/showthread.php?p=854200#post854200) out there.:)

[EMC2]

You may have to add a pot to the 1st stage control Malves to get much over 4V... opposite side of the dual amp ;)

Peace :toast:

[celemine1Gig]

Interestingly enough, it seems to be the exact same voltage regulation circuit like on the DFI LP NF3. :)

[Barr3l Rid3r]

how can I measure vcore and vchipset in that board?

[G H Z]

Malves have you or anyone seen the NF3 939 DFI? I want a vio mod for it also.

[Malves]

Nope, haven't seen that board yet, bro. I don't like vio mods, sorry.

Just to add, VTT tracks just fine on this board. VTT check is the top leg on that same mosfet (where you check vdimm) in that pic.:)

[EMC2]

Barr3l --- Look here for all V measurement points (http://xtremesystems.org/forums/showthread.php?p=777631#post777631)

Just to add, VTT tracks just fine on this board. VTT check is the top leg on that same mosfet (where you check vdimm) in that pic.:)Depends... put in 2x512 with >250Mhz Memclock and run Memtest T8 with VTT instrumented bro ;)

Peace :toast:

[Malves]

Hmmm...didn't know that. I don't have a cpu to run that test.:(

[timpanogos]

"just to add, VTT tracks just fine on this board. Vtt check ..."
"depends ... put in 2x512 with ..."

what language are you guys speaking?

Can you tanslate to gumbie?

what is Vtt? and what does it have to do with vdimm and chipset voltage, and 250memclock with 2X512 and some processor needed?

boy am I lost or what?

Chad

[stealth17]

"just to add, VTT tracks just fine on this board. Vtt check ..."
"depends ... put in 2x512 with ..."

what language are you guys speaking?

Can you tanslate to gumbie?

what is Vtt? and what does it have to do with vdimm and chipset voltage, and 250memclock with 2X512 and some processor needed?

boy am I lost or what?

Chad

vtt is half of vdimm. its very important and if it gets too high or too low of the vdimm then stuff wount work right. some boards need a vmod to make the vtt right while the dfi nf4 seems to keep it okay by itself. what EMC2 is saying is that if you run 2x512mb ram at >250mhz and then run memtest #8 then the vtt might go off a bit. i think thats what he is saying

[timpanogos]

Interesting, and I assume the bios has some effect on this tcc as well as vdimm control .. in as much as I have heard some saying that the 5-15/18/23 bios has left them super-pi unstable at previous oc's etc.

What are some of the symptoms that are seen on "other boards" that lead to the vmods? Are there certain ras/cas/drive strength etc. types of settings that corrolated with vtt problems (i.e. some vtt mod allowed for setting x to be tightened to y)

Thanks!!

Chad

[EMC2]

"might go off a bit" is putting it mildly :lol:

--- Chad --- Vtt is used by the memory and the CPU as a reference signal to tell when a signal is high or low. It's also used in the termination networks for the signals on the MB to...errrmmm...in "gumbie" as you put it... to make the signals better. What I was telling Malves is that under certain conditions the Vtt fluctuates a lot causing errors. What he was saying is he doesn't have a CPU to put in the MB to check out what I told him.

--- Malves --- Vtt is rock solid stable until certain burst data patterns are used... then it fluctuates quite a bit... enough to cause ~25Mhz OC difference :( It appears to be a load issue, as it's relatively long term fluctuations (you can see them with a DMM). You can run T5 (pretty much T1->T7) and it's rock stable... T8 and it's all over the place during the course of the test. You can pretty much predict when errors will pop up by monitoring where Vtt is. Same thing happens when in Windows... and when running most benchies. Note that both the input rail and the reference to the VTT regulator remain rock solid... it's only the VTT output of the regulator that fluctuates.

Peace :toast:

[Malves]

Interesting. So, maybe a VTT mod could help?:)

Also, I haven't mentioned before, but I knew the LM328 just uses 2nd stage for both 3.3v and 5v. The switch between both should be via jumper, not the stages. So, with that said, I got vdimm up to 4.5v via trimmer, using JP17 @ 2-3.:D

Those that want more control over their vdimm and those that are brave enough for 4+vdimm, this is the mod.:D

[stealth17]

wow cool stuff

so malves, think you could make up a vtt mod?

so all we do is put the jp-17 in and we can get higher than 4v with the trimmer in the same place right?

[G H Z]

Nope, haven't seen that board yet, bro. I don't like vio mods, sorry.

Why don't you like Vio mods?

-sorry for more OT ;)

[EMC2]

Malves - ygpm :)

[Malves]

Thanx for the heads up, bro.;)

Well, EMC2 mentioned in his PM, it looks like under load the 1st stage of LM358 limits the 2nd stage to ~4.2v. So, under load, vdimm @ 4.5v may not be possible.
Unfortunately, I don't have the right equipment and not enough of it, too, to test all of this, but I guess EMC2 has been there.

Vio mods don't give you any control over vdimm, that's why.

[timpanogos]

It's info like this that has me now watching this site/forum closely ... thanks all great info

[Waus-mod]

Why a vdimm mod if you can use the bigtoe mod? the only thing is to fake the 5v jumper. no soldering. Why should i still prefer this mod?

[timpanogos]

I believe the "bigtoe mod" is to slide the block connector down one row, put it on the 3.3v side and single jumper the exposed top pins from the center to 5V side.

This is the jumper that allows the bios to set voltages over 3.2. However, you are now on teh 3.3 volt rail, and being able to set actual voltages above 3.2 will be based on if that voltage is available on the 3.3v rail. With supplies like the OCZ the supply allows you to tweak this, on others, you'll need to vmod.

However, Malves has warned me that setting the bios higher than what is available on the rail could damage the mobo. So you might want to be careful with the BigToe mod, making sure your rail is over what the bios is going to try and put on your memory. Also be aware that my bios/mobo/etc. seems to overvolt the mem by about 0.08, so I assume you best have your rail overvolted by at least that same amount from what you plan on setting in your bios

[Malves]

However, Malves has warned me that setting the bios higher than what is available on the rail could damage the mobo.

I remember reading something about this, but I can't remember where. :mad: So, don't take my word for it. :)

[stealth17]

the bios will only go up to 3.3v and then you just adjust the rail and nothing more in the bios. there isnt an option for a higher voltage so unless you 3.3v rail is less than 3.3v then there will not be any problems

[Waus-mod]

It really works great on my board. setting my ocz to 3.8v and i gain a stable 3.7vdimm. Works truly great!

are there more mods for the nf4 ultra-d?

[Malves]

It really works great on my board. setting my ocz to 3.8v and i gain a stable 3.7vdimm. Works truly great!

are there more mods for the nf4 ultra-d?

Which one? Bigotes'? There's vcore mod, but i don't think anyone will need it.:)

[Waus-mod]

And the vtt?

[stealth17]

wow vtt does suck. specs in my sig, i was running 275*8 at 3.6v (bios) and the actualy vdimm was 3.7v the vtt was all over the place. it jumped from 1.83v up to 1.87v! ouch! it was anything but close to stable but the 3.7v was satble although i did see it jump to 3.71v for a second a time or two.

anyway, can we fix the vtt atleast somehow?

[EMC2]

I've recorded fluctuations of ~80mV when nominal VTT was 1.455... most of it in the negative (lower V) direction... about 3x what it should be.

Here's some pics from an o'scope... sorry for the graininess... frames from a video capture with a digi-cam :lol: These are taking running T8 of memtest, the large steps are when the test pattern changes between mostly 0 patterns to mostly 1 patterns:

http://xtremesystems.org/forums/attachment.php?attachmentid=33199&stc=1
http://xtremesystems.org/forums/attachment.php?attachmentid=33200&stc=1
http://xtremesystems.org/forums/attachment.php?attachmentid=33201&stc=1
http://xtremesystems.org/forums/attachment.php?attachmentid=33202&stc=1
http://xtremesystems.org/forums/attachment.php?attachmentid=33203&stc=1

Peace :toast:

[Malves]

EMC2, do you think replacing/adding the "VTT caps" would help with the fluctuations?

[timpanogos]

quick explination of vio please ... I know you said you did not like/use it, just wondering what it is ..

Thanks

Chad

[Malves]

vio = 3.3v rail of your PSU

[EMC2]

Malves... slightly, for helping some with the relatively shorter term fluctuations like the small bumps in the 3rd scope pic that occur before the step change... but not for the longer term changes that start/end at the step points. Note the scale on those pics is 5ms/div... and the larger step changes last for upwards of seconds (as long as the offending pattern is being burst). Basically the VTT is drooping due to the current demand and the internal FETs RdsOn. Can think of 3 fixes... 1 that positively would work... 1 that has a 90%+ chance... and one that is 50/50 (which I'm not willing to sacrifice my MB for).

Peace :toast:

[timpanogos]

sounds like I did the sio mod that you do not care for. I am interesting in going ahead and doing the op-amp mod that was shown as the topic of this thread. However, I'm still confused, without the sio mod, how can the opamp mod help, on my vx that want 3.3+ volts?

I would be interested in your "droop" mod also .. any info is appreciated ...

Chad

p.s. can you elaborate on why you do not like the sio mod

[EMC2]

Just a little update on the Vtt side of things... was looking at it and a few other things with better equipment and got a nice capture of a Vtt step. Did a rough calc on the capacitance needed for this... can't get there from here, it comes out several farads worth :lol: However, I did find that drive strength has an effect on the magnitude of the step, gained some Mhz, along with enough info to base fixes on :D Now to find time and parts ;)

Capture of Vtt step on DFI nF4 - this one occured during transition from an FFFFFFFF to 00000000 based modulo:
http://img8.echo.cx/img8/6034/vttvmemttdip4annotated7hz.png (http://www.imageshack.us)

Peace :toast:

[JNav89GT]

wow, I feel stupid now :(
time to go off to get my 3rd degree, this time as EE so I can understand this stuff.

Maybe I speak in medicalease so I can feel smart.

[stealth17]

definatly a big problem. hope you can help us EMC2!

[craig588]

How much does a fancy scope like that run?

Hmm, back on topic, I would love to perform any mods required to fix this problem. Unfortunately the only thing I know how to do is look up chip specs and reduce resistance on the sense leg, which is probably where pretty much everyone else here also hits there limit too; we are all betting on you EMC.

[EMC2]

time to go off to get my 3rd degree, this time as EE so I can understand this stuff.

Maybe I speak in medicalease

It's easy to understand John... just imagine that Vtt is your blood pressure and an equivalent event would be your BP dropping to 70/40 for a few moments when you first see a really fine bikini bendover due to increased blood demand ;)

--- Craig --- More than I would spend for personal use...

Coming up with fixes is easy... doing one that is affordable and can be done by most is a bikini of a different color :lol: Until then, my suggestion is to use Memtest T8 to fine tune your drive strengths ;)

Peace :toast:

[timpanogos]

I'm currently running on a sio mod, 3.5 volts. But still planning on doing the op-amp mod.

emc2, am I reading your last scope right ...1.38V *2 = 2.76 vdimm - so it looks like you are using tccd (or other lower voltage mem).

1. Would you expect that vx, at 3.38 vdimm types of voltages will also show as dramatic of load dips?

2. were you lowering or raising drive/data strength to reduce the fluctionations. Any suggestions for vx types of voltages I've been running 8/3 just reduced to 7/2 and running test 8 for the night to see how it acts.

Thanks for the information/work on this

Chad

p.s.

3. when analyzing voltages at this level of detail ... do orange/yellow slots make any difference?

4. exactly what brand/model of memory are you using for this test?

[stealth17]

yeh i am kinda wondering too... TCCD pulls more amps. thats why it uses less volts. what ya think?

[EMC2]

--- Chad --- Ummm... look at what C2 is labelled as ;) Nominal Vtt is 1.455 for that test run... and yes, for that test I was using TCCD.

1) Yes

2) This weekend I'll be back on high volt mem, let you know then regarding #s. From what I've seen to date, lower drive strength (based on info about which way the numbers run on DFI) lessens magnitude of the drop... but too far of a drop and you loose Mhz from edge rates slowing down... it's a balancing act with stock Vtt config. Oh... and think about what kind of memory needs higher drive strength ;)

--- Malves --- based on some other info I uncovered today, this board definitely could benefit from better high frequency decoupling on Vmem and Vtt...

Peace :toast:

ps :p:
3) Not as far as this Vtt issue goes...

4) I'll post that elsewhere later ;)

[persivore]

Does anyone want me to try to design a fix for the Vtt droop problem?

[THunDA]

Trying to find where I read about board being damaged if selecting vdimm in BIOS > 3.3v rail. Can't find it, thou.:(

Your 100% right.. I cant find where I read it either..

But I think it was one of the OCZ guys that said if your using the BigToe mod and raise the vdimm past what your 3.3v rail is set to it will cause major problems and might damage the mobo..

[timpanogos]

on vx, drive=7, data=2 tested well over night - #8 no errors (I was 8/3 and was getting about 5 #8 errors in a 6 hour period)

[Malves]

--- Malves --- based on some other info I uncovered today, this board definitely could benefit from better high frequency decoupling on Vmem and Vtt...

Waiting your PM with more details.:D

[Ubermann]

Does anyone want me to try to design a fix for the Vtt droop problem?

Plz do.
What more mods are there for this board, if any at all ?

[stealth17]

Your 100% right.. I cant find where I read it either..

But I think it was one of the OCZ guys that said if your using the BigToe mod and raise the vdimm past what your 3.3v rail is set to it will cause major problems and might damage the mobo..

but the highest option in the bios is 3.3v when using the bigtoe mod :stick:

[craig588]

Nope, I have 4V avalible. I have also used the 4V option while running off of the 3.3 line just to figure out how much voltage is lost from the 3.3 line to the memory, my board is undamaged and my 3.3 line was only at 3.8V. (Just if you are wondering, it's about .2V less than the 3.3 line)

[EMC2]

Well... after another round of the Java dance I found that the Vtt issue is a bit more Xtreme than I thought...

Ran a little Spi1M and saw this:
http://img146.imageshack.us/img146/9086/vttduringspi32m4cr.png (http://www.imageshack.us)
Then during the initial ramp-up of OCCT, I saw this, about same magnitude as the Memtest T8 drops, but shorter duration (like the Spi1M dips too):
http://img8.imageshack.us/img8/7164/normalocctdips5lo.png (http://www.imageshack.us)
Then this is what showed up just as OCCT failed:
http://img146.imageshack.us/img146/7984/occtdip18sn.png (http://www.imageshack.us)
After giving it another go I got this "beauty" after about 5 mins:
http://img146.imageshack.us/img146/4841/occtdip21ek.png (http://www.imageshack.us)
Funny part... this was at sub-standard clocks speeds :lol:

Notice the captures regarding Vtt during OCCT failures are much worse than the MemTest8 ones. Those are about a 17% deviation from what Vtt should be. The part used is rated for 3% regulation. Hmmmmmmmm.......

Those "OC's like a formula 1 car today, won't run at stock next day" comments are starting to make sense...

Oh well, it's Java time :toast:

[stealth17]

Nope, I have 4V avalible. I have also used the 4V option while running off of the 3.3 line just to figure out how much voltage is lost from the 3.3 line to the memory, my board is undamaged and my 3.3 line was only at 3.8V. (Just if you are wondering, it's about .2V less than the 3.3 line)

opps i guess there is a higher option, sorry my bad :rolleyes:

i tried having my 3.3v rail at 3.87v and set the bios to 3.7v and i got 3.7v but the fluctation was HORRIBLE. the vdimm went down to 3.56v in memtest #5 :( this is on a OCZ Powerstream 600watt...it didnt fluctuate though when i have it at 3.8v and set in bios to 3.6v. i saw .1v fluctuation but thats about standard with the crappy circuitry

-----------
@ EMC2
-----------

WOW! its sad that the vtt sucks that bad. thats just amazing how much it drops in OCCT! hmmmm and a cure would be------ :slapass:

[OzSnoal]

Great findings, actually, not so great findings.

A question, Vtt where is it connected to on the CPU and RAM (a pin number would be nice)? I want to read on it.

I'm guessing it is pin 1 of the DIMM, otherwise known as Vref (not to be confused with your Vref indicated in your measuring points). Am I correct?
Well, if someone could point me in the right direction...

What I don't understand, if it is 'just a reference' for the CPU/RAM to 'know' what is a logic 0 or 1, what is loading it so heavily? What is the expected current draw from the VTT source?

[Malves]

You can pick either leg circled in yellow, for VTT reading.

[stealth17]

You can pick either leg circled in yellow, for VTT reading.

pic doesnt show up....no access permission

[timpanogos]

did some intense re-tunes the last few days running on the 623-2 bios.

I'm superpi, memtest, 3dmark05, 3dmark03, 3dmark2001, aquamark3d, S&M (long), OCCT and Prime95 stable --- at stock 200*13 1.5.2.2.5 (all others tight)-- I've also got an alternate set of loose timings which also pass all benches -- 200*13 2.3.3.10 (all others loose)

I'm 240*12 1.5.2.2.5 stable for all of the above -- except OCCT/Prime95 and S&M (cpu ok, mem fails 2nd test)
Same for 240*12 2.3.3.10, 250*11 1.5.2.2.5 and 250*11 2.3.3.10

I tried many things to get prime95 stable at the OC's to no avail!!

After seeing your OCCT scoped vtt - I'll bet prime95 does the same thing!!

If you experts get/have any mod's please pm me, I will try a mod.

Chad

p.s.

you can see my exact settings for these benches here

http://www.dfi-street.com/forum/showpost.php?p=151154&postcount=116

p.s.s sorry about the dumb comment on the pm me ... just willing to try something, even if it's not ready to publish.... like everyone else here ...

[stealth17]

lol we all want a mod. havent you read the thread? if they pm you one, we cant see it :p

[uwackme]

Good catch bunky.

Not great news, but a good reason why higher than 3.4V makes not improvemnt beyond 250Mhz on my 2 DFI SLI boards with either UTT-CH or UTT-BH or OLD-BH5. If vtt is falling apart above a certain point, sheesh.

Esp points out why the New-BH (ValueVX) were having Test #8 errors with 1T _and_ bankinterleave enabled.

Simple experiment to generate further data. Anyone with a OCZ booster...which drives Vtt/Vref as well as Vdimm and might take up the slack and provide stable Vtt. Checking the voltages/stability with the booster installed would give as more data points.

Guess we'll have to collaberate on a DFI NF4 Vtt project, like we did for the NF7-S last year.

THINKING CAPS ON :cool:

[timpanogos]

I have a new booster, but no o-scope - willing to mail it off to emc2 for this test

p.s. I'll go tear down my beautiful overclock and stick the booster in to see if I can get a ottc pass at 250*11 -- report back later

Chad

[Malves]

VTT does not need a mod. It needs a fix. It tracks vdimm, but really bad.

Picture in my previous post above has been fixed.

[uwackme]

Thats what I mean Malves. The booster will over-ride the Vtt from the NF4 regulator as it is also a regulator. So hopefully it will provide enough extra current to keep Vtt stable. The result should be a high stable overclock.

So Vdimm stays rock solid through all this, just Vtt gets the shaft?

[OzSnoal]

EDIT: Never mind about below, found it in the AMD datasheet - I should've looked before asking ;-)

Malves, I would like to know what VTT is connecting to, i.e. to which pin on the processor, to which pin on the DIMM slot. Got the pin, I got the details to look things up on.

From a technical point of view I want to read about how and where VTT is used, and looking at datasheets without knowing that, well, is like looking for a needle in a haystack.

Thanks

[tennvols_69]

what about changing out the vtt regulation ic with a better quality one? or adding caps to help stabilize the signal.

[craig588]

EMC said it would take a few farads of capacitence to fix the fluxuations so extra capacitors are a no.

[Malves]

560pF if I remember right. Should give you an extra 5mhz in o/c. Too much hassle for so little gain.

[sluggo]

What is the Vtt regulator using for gate drive? If it's 3.3V (with the jumper in standard position) and 3.3 gets pulled down momentarily or gets noisy, it could drop below Vin briefly. The Vdimm reg might ignore it - this one might not. Just a maybe.

sluggo

[PORTUGAL]

this problem possible cold be caused by autooscilation in the integrated circuit,wath about trying adicional eletrolitic capacitors in the input and the output from the regulator.

[dippyskoodlez]

560pF if I remember right. Should give you an extra 5mhz in o/c. Too much hassle for so little gain.

something like this, or am I way off?

http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=358960&e_categoryid=303&e_pcodeid=58114

[persivore]

I'm a bit busy atm to work on a fix for Vtt atm. I should be able to get it done by the end of next week. If anyone wants to work on it instead of me doing it, feel free to do so :).
What I have in mind is to use an opamp between the reference voltage pin on the Vtt regulator and the voltage divider which is used to make Vtt follow Vdimm, and use the opamp to provide feedback to correct the voltage. This will involve lifting one of the pins of the Vtt regulator off the board, however.

[Malves]

This will involve lifting one of the pins of the Vtt regulator off the board, however.

Piece of cake.:D:p:;)

something like this, or am I way off?

http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=358960&e_categoryid=303&e_pcodeid=58114


Yup, but size 0603. According to EMC2. :)

[craig588]

Lifting a leg is easy, lifting the whole thing would be hard.


Another thing, that seems like a very small capacitance, I have caps rated for thousands of microfarads in a drawer right next to me. Why can't I just use them? I thought I saw multiple farads somewhere which would have been pointless to try to reach, but 560 picofarads is really easy to reach.

[tictac]

this one?
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=362684&e_categoryid=302&e_pcodeid=58113

[PORTUGAL]

can someone post an image with the exat points to soldering the 560pf capacitor?

[OzSnoal]

Normally pf caps are used to filter noise.

Maybe this has been posted before, nice software I came across:
http://www.kemet.com/page/spicesoft

It shows a graph of impedance vs frequency for your selected capacitor.

Select your Chip Type/dielectric for your capacitor and it will show you a graph of impedance vs frequency, a 560pf COG 0603 has its lowest impedance at approx 166MHz. It's a nice toy if you want to pick a cap for a specific frequency. And an 0805 of the same part shows the lowest impedance at 190MHz.

[EMC2]

--- stealth17 ---
Go read the 2nd page of my post on the Zippy/PCPnC fix thread for why you see the fluctuations you do with those settings ;)

--- OzSnoal ---
Vtt and Vref are two different signals, depending on where you look at them.

Vref - used for what it's name implies, a reference signal to determine the mid-point of the memory signals. It's an input to the Vtt regulator and is shown in the scope pics.
Vtt - this is the signal termination voltage used to supply the termination networks on the signal lines to/from the memory. If you look at your MB, you'll see nice long rows of termination networks. The loading occurs as a result of the current through these termination networks to the memory signals.

If you want to read information on what it's all about, go look at design guides from memory manufacturer's...

For where to look at the signals in general, they are shown in this post of mine: http://xtremesystems.org/forums/showpost.php?p=777631&postcount=10

--- uwackme ---
bunky? :rofl: Yes peaches :p: Vdimm stays rock stable... look at the scope pics again, it's all there ;)

--- Malves (and all) ---
The 560pF caps are for the main frequency components of the noise that is prevalent on Vtt and Vmem - they are NOT for the problem shown above in the scope pics and being discussed. And just one won't help ...

--- sluggo ---
The regulator is using Vmem for both it's input source and it's gate drive... the point instrumented in the pics for all 3 signals is at the Vtt regulator. It is not an input signal droop issue.

--- Portugal ---
One possibility... and it may be being set off by transients... work in progress ;)

--- persivore ---
That is actually one of the possibilities I mentioned to Malves... but to be done right need a small PCB or protoboard. All connections can be made at the Vtt regulator btw ;)

If it is a pure load issue, you could possibly parallel another regulator... would require a small HS and good soldering...
Or another alternative is replacing the existing regulator with a different circuit :hehe:

--- everyone ---
Patience :p:

Peace :toast:

ps. Oz - set it to NPO dielectric and 25V rating... it's 300Mhz centered for an 0603... an 0805 will have a lower frequency center than an 0603 due to the packages higher inductance ;) And I use AVX caps... hate kemet :p:

[stealth17]

--- stealth17 ---
Go read the 2nd page of my post on the Zippy/PCPnC fix thread for why you see the fluctuations you do with those settings ;)

what thread?

http://www.xtremesystems.org/forums/search.php?searchid=662302

[EMC2]

The sticky... Zippy and 850SSI ;)

[stealth17]

The sticky... Zippy and 850SSI ;)

it didnt help :(

vtt is still everywhere

[sluggo]

Okay, so assuming this part (the 9173A) is used successfully on other motherboards, then this is either a bad lot of parts or a bad implementation/layout on the DFI boards. If it's a bad lot of parts then mod results may be unpredictable. If it's a bad layout (my choice), it's usually because they've got the bypass caps too far from the part. Wish I could help but I can''t put my board on the bench right now :(

sluggo

*edit* Sorry - I'm jumping to conclusions here. Obviously, there's many more things that it COULD be, and I'm just shooting from the hip.

[stealth17]

i know this is a tiny bit off topic but not really.

http://img67.imageshack.us/img67/4947/themissinglink7fv4io.th.png (http://img67.imageshack.us/my.php?image=themissinglink7fv4io.png)

look at the position of the jumpers i put in that pic. they are the big black squares. notice there isnt one on row B. here is my thinking:

i was doing some testing with no dimms and power ac off, then switch it on and measure the dimm voltage. with rob B jumper on 1->2 i get 2.4v something. with it in 2->3 i get 2.75v, higher than in the other side. if the vdimm controll is messed up, its obvious you will have voltage to the dimms as both pins (1,3) feed from the 5vsb rail. so i was thinking, what if you dont put a jumper there at all and connect the regular 5v rail to B2 (the blue block)? it wouldnt get voltage untill the mobo is acutally on, thus bypass caps are not charged.

i tried the cold boot find steps with no jumper on the B block and i didnt get any voltage to the dimms with the ac power on.

what do you guys think?

[OSKAR_WU]

memtest #8 loop , fx-57 , 300 * 9 , gskill 512mb tccd * 2 , 2.87V mem , 1T

Scope Channel 1 : Pin5 in RT9173A VTT regulator
Scope Channel 2 : VTT rail behind DRAM slot
Scope Bandwidth 20mhz

http://oskarwu.myweb.hinet.net/1.mpg
http://oskarwu.myweb.hinet.net/TEK00000.gif
http://oskarwu.myweb.hinet.net/TEK00001.gif
http://oskarwu.myweb.hinet.net/TEK00002.gif
http://oskarwu.myweb.hinet.net/TEK00003.gif

[Ubermann]

God just entered the building.

[timpanogos]

Oskar, I've always been able to tweak memtest #5 and #8 to pass ok ... it's OCCT and Prime95 that I could never get to pass.

Please test/provide shots with OCCT running so we are looking at the same thing as emc2.

I'd also be very interested in seeing prime95 shots.

try right off with like 250*11 @2-2-2-8 on some vx type memory for your run, and capture the time frame right were it fails.

Chad

p.s.
I've been working hard to make the dfi oc database, I was stuck at stock (could not prime) until I put the ocz booster in - you can look here for detailed settings/benchmark screens.

going for a Johnnylee 24 hour run to to be able to post here ....

http://www.dfi-street.com/forum/showthread.php?p=152782#post152782

[EMC2]

Hi Oskar :D

Winnie @ 9x295
Memory TCCD on BP0815 PCB, 512MB per stick,
running @ 295Mhz, 2.5-3-6-3-9-12-2-2-2-3-4708, 1T, 2.91V
BIOS 510-3fixed, DDS=3 ,DS=7 ,Tref=4708, Interleave ON, 256 Idle cycle count

Scope Channel 1 : Pin5, RT9173A VTT regulator
Scope Channel 2 : Pin3, RT9173A VTT regulator
Scope Bandwidth Limit set to 20mhz

Here's MemTest8 with ONE 512MB DIMM - Vtt as it should be ;)
http://img301.imageshack.us/img301/3192/memtest81by512mb8jw.png

Here's MemTest8 with 2x512MB DIMM, TCCD, BP0815 PCB - considerable change due to load (>6x) :( I see higher than you... RT9173A lot difs or CPU?
http://img301.imageshack.us/img301/4439/memtest82by512mb8pt.png

Here's what you get from a dynamic load change in windows, Windows MemTest, much worse:
http://img301.imageshack.us/img301/244/windowsmemteststop0hi.png

Here's one from during OCCT, again, bad stuff:
http://img301.imageshack.us/img301/2875/occtstop1ew.png

I have more pics from the session (including equipment) and AVI videos of the captures (low quality, but hey). However, I need either 150MB of web space or an FTP site at DFI to upload them to if you want to see them.

Peace :toast:

[EMC2]

--- Stealth ---
You only have voltage on the DIMMs with AC ON and MB OFF until you boot up one time. After that, when you shut down (MB OFF) the power is removed from the DIMM circuits. The moral is, don't change DIMMs with the Vmem power LED on ;) Oh... and I think this would be better discussed in the PCPnC/Zippy Fix thread :D

Back to the topic at hand...

[EMC2]

Ooooooops... forgot another case/data point from Friday...

Same setup as above, but during windows boot-up...
W2K, just after initial screen with scrolling bar at bottom, when the video gets switched over to the desktop resolution (going from VGA to 1280x1024) and video memory loaded (video is momentarily blanked during the switch) you get something a tad worse than the OCCT and Memtest screens above.

[OSKAR_WU]

The worst case will be all 0/all 1/transitient from all 0/1 to all 1/0 ... The minimal RTT total equivalent resistance in dual channel mode will be around 0.7 OHM ... If the VTT is set as 1.45V , maximum IL in both sink/source mode will be around 2A ... Still within the range of the spec of RT9173A ... RT9173A can control the VTT output within 2% of variation if the IL from -3A to 3A or so ... What you measured should not be a typical result from the design spec ...

[EMC2]

I agree... based on the spec for the RT9173A it should not change that much if max load current is 2A. If it is 2A then... bad batch of RT9173A's? Or maybe because VCtrl = Vin instead of VCtrl > Vin. The spec'd output variation is with Vctrl=3.3V, Vin=2.5V.

Note: Not a temp issue either... 120mm fan over DIMMs and covering Vtt/Vmem regulator area... Vtt regulator is cool to the touch.

[flexy]

hey, i just found this thread. Whow...

I am having the same issue that i can run memtest #5 and #8 for hours.....but i cr*p out with OCCT in Windows in 10 seconds at a certain, given dimm.

I used to run my TCCD at 2.9V....and (dont ask me why)....there is an issue with either )the board )PSU )memory ...that my sticks now need MORE and mroe voltage otherwise i cant be stable in OCCT at all.

2.9V is now a total no go so is 3.0V ...i need to push my TCCD (week 37) with 3.1V so i can get stable in OCCT ! (yes, TCCD !!!)

It looks you guys are sitting on the source of MOST instability problems in windows/OCCT....looking at that readings makes me shudder !

I hope you can come up with a solution ! Great reads and insights here !!!

[flexy]

Those "OC's like a formula 1 car today, won't run at stock next day" comments are starting to make sense...


ok..i KNEW i am not alone :)

Btw. so it looks like the OCZ booster may fix this ?????

[timpanogos]

Hey my findings are circumstantial and nowhere as scientic or accurate as that scope, only true test is for someone to scope the booster's supplied vdimm/vtt fire up occt and take a look

I’m new to all of this, don’t take my word .. I’ve just fought that prime95 stable from day one, and would love to have a solid, yes that’s it, or no, back to tweaking answer to my personal journey/mystery


Chad

[flexy]

yes i am waiting for someone replying who has scope readings using the booster.

Also...i know that i know FAR less than those guys in that thread here....but i had a few thoughts....and i saw some postings [EMC noted he saw drops while the video initialized] which made my thoughts even more interesting:

<> monitoring VTT *NOT ONLY* when under load with OCCT/Prime95.
WHEN does this happen ?
I say this because ever since (and still) i get occasional BSODs eg. while i am literally doing "nothing"...just with FireFox open or browsing thumbnails on HD.
There *might* be situations where the vtt drops down other than OCCT/extreme load. Just an idea.

<> they already said there's a relationship "drive strength" <---> vtt drop "extent". I wonder if there is a relationship "VTT drop" <--> "Vdimm voltage".
I am wondering this because right now i am experiencing this extremely bizarre fact that my TCCD needs 3.1V and is not stable anymore at eg. 2.8 or 2.9 i had it before. (same bios settings of course).

Is the increased VDIMM "somehow" compensating or influencing the drop of VTT ? (I say this because i cant explain otherwise why my TCCD want 3.1V, i never heard of TCCD wanting more than 2,9 or so...but it's the case here)

Just my $0.2

[stealth17]

yes i am waiting for someone replying who has scope readings using the booster.

Also...i know that i know FAR less than those guys in that thread here....but i had a few thoughts....and i saw some postings [EMC noted he saw drops while the video initialized] which made my thoughts even more interesting:

<> monitoring VTT *NOT ONLY* when under load with OCCT/Prime95.
WHEN does this happen ?
I say this because ever since (and still) i get occasional BSODs eg. while i am literally doing "nothing"...just with FireFox open or browsing thumbnails on HD.
There *might* be situations where the vtt drops down other than OCCT/extreme load. Just an idea.

<> they already said there's a relationship "drive strength" <---> vtt drop "extent". I wonder if there is a relationship "VTT drop" <--> "Vdimm voltage".
I am wondering this because right now i am experiencing this extremely bizarre fact that my TCCD needs 3.1V and is not stable anymore at eg. 2.8 or 2.9 i had it before. (same bios settings of course).

Is the increased VDIMM "somehow" compensating or influencing the drop of VTT ? (I say this because i cant explain otherwise why my TCCD want 3.1V, i never heard of TCCD wanting more than 2,9 or so...but it's the case here)

Just my $0.2

my tccd needed atleast 3v to do anything...week 449. but that doesnt explain why you were stable at 2.8 and need 3.1 now...

[timpanogos]

fwiw, based on emc2 comments in various places, I did back my drive/data strengh down ... I got my dfi-street oc database stable entry (and 24 hr prime stable here) with 6/2 - I had been running this at 8/4 (8/3 in later bios)

Chad

[flexy]

tony at ocz did a simple vdimm mod
http://www.bleedinedge.com/forum/showpost.php?p=99780&postcount=1

and he claims this mod gives very good results, eg. where he needed 2.9v/3.0v before (TCCD) he can now do with 2.6 !!!

He doesnt have an explanation, but one of his theories is it COULD provide better VTT with that mod. <--- ? (Which needs to be proven w/ scope which i dont have !)

ALso..from what i READ now the ddr booster does NOT solve VTT issues ! Still.....it would be interesting to see how the ddr booster does (scope/occt).....if it does NOT provide better VTT then it must be doing something ELSE, which, in term leads to a cleaner VTT.
(And here we are again with my speculation whether there is some relationship VTT <--> VDIMM voltage).

This is one of the MOST interesting threads btw.

[stealth17]

tony at ocz did a simple vdimm mod
http://www.bleedinedge.com/forum/showpost.php?p=99780&postcount=1

and he claims this mod gives very good results, eg. where he needed 2.9v/3.0v before (TCCD) he can now do with 2.6 !!!

He doesnt have an explanation, but one of his theories is it COULD provide better VTT with that mod. <--- ? (Which needs to be proven w/ scope which i dont have !)

ALso..from what i READ now the ddr booster does NOT solve VTT issues ! Still.....it would be interesting to see how the ddr booster does (scope/occt).....if it does NOT provide better VTT then it must be doing something ELSE, which, in term leads to a cleaner VTT.
(And here we are again with my speculation whether there is some relationship VTT <--> VDIMM voltage).

This is one of the MOST interesting threads btw.

good find but it is the same thing as Malves mod in this thread (1st post) im pretty sure. basically connecting pin 6 to ground, malves used pin 4 for ground while Bigtoe used the ground on JP17 block.

see--> http://img8.echo.cx/my.php?image=themissinglink7fv.png

if pin 4 is not ground then its not the same but id think it is

[persivore]

I don't think that a DDR booster will have any effect on the stability of the Vtt supply. AFAIK the booster only supplies the Vdimm, and doesn't effect the Vtt supply, unless the Vtt regulator on the motherboard tries to follow the Vdimm set by the DDR booster.

[tmogi]

Maybe this explains why hynix or other generic value rams which usually requires stronger drive strength doesnt work well on this board?
Very interesting thread indeed.

[uwackme]

Well, the Booster needs to affect Vtt, since it is altering Vdimm and Vtt must TRACK 1/2 Vdimm. Vdd Vddq Vref and Vtt all must track correctly. On DDR main ram Vdd and Vddq are just connected....as opposed to GDDR2/3 on video cards were they are seperately controlled to precisely nail maximum ram speed.

So Vdimm(Vdd/Vddq) and Vtt(Vtt/Vref) are DIRECTLY related at all times, unless you have a sucky DDR voltage regulator design, like the NF7-S did, where Vtt did not correctly track, and required a seperate Vdimm and Vtt mod to achive high Vdimm and correctly tracked high Vtt.

On the TCCD issue, you may be right, that the Vtt is the root of why higher Vdimm is needed. You end up raising Vdimm to the point where the "MAX LOW VALUE" on Vtt is high enough for the ram to be happy. That fixing this droop would allow a much LOWER Vdimm for TCCD is likely.

The scope doesnt lie, that droop we are seeing is real and it needs to be eliminated. Perhaps the calculations are wrong and the Vtt load is alot higher...on a transient/instantaneous basis...and the design needs some help.

I asked about the booster because it would have to generate a bump on Vtt too, and maybe setting the booster to match the Vdimm/Vtt of the motherboard would effectively DOUBLE the output current rating of the regualtor circuit NET, since both MB and Booster regulators would be feeding the Vdimm/Vtt bus's. Alot like getting another 9173A and soldering it on top of the original doubling the output.

improbving the Vtt regulators output with caps as well would entail adding a 560pf, a .1uf, and a 2200uf electrolytic to cover all spectrum of signal transients.

Remember, yes a 560pf is fast enough to respond to the transient edge, BUT it contains so little charge it cant actually make up for the deficit in instantaneous current needed at the 0's to 1's transistion in Test #8, for example.

I believe the 9173A's will run OK in parallel, so I guess we need to experiment with soldering in a second one. Some AS Ceramic goop on the bottom 9137 then piggy back, bend the 2nd one's pins down and solder it inplace over the original. Find a spot farthest from the regulator output...like one of the .1uf bypass caps for the Vtt resistor arrays, and solder the 2200uf electrolytic there, add the 560pf/.1uf ceramic caps to the regulator output pin. (each one cap to Vtt, othersie of cap to a good ground VERY cloe to the cap).

[Malves]

good find but it is the same thing as Malves mod in this thread (1st post) im pretty sure. basically connecting pin 6 to ground, malves used pin 4 for ground while Bigtoe used the ground on JP17 block.

see--> http://img8.echo.cx/my.php?image=themissinglink7fv.png

if pin 4 is not ground then its not the same but id think it is

Yes, it is the same vdimm mod. Pin 4 that I use is ground. Really doesn't matter what ground you use.

Hey EMC2,

Maybe it's time to test the board on the scope with the vdimm mod.

[flexy]

well just out of curiosity (and since my name is George :) ) i took my DMM and watched VTT - of course it totally confirms what EMC said. Clearly visible on the dimm.

Start OCCT and you can literally see it crashing on the DMM when the VTT drops down like 10%-15%. Voltage down --> crash :)

If i had the parts i would do the voltage mod just to see what happens then, but i dont have a VR right now to solder.....waiting for results by others.

I STRONGLY tend to say that this is a (previously) overseen board/design flaw because we are so MANY people with inconsistencies in their overclocks and the same issues....so i am very much looking forward for a fix to keep that VTT steady.

[flexy]

to achive high Vdimm and correctly tracked high Vtt.

On the TCCD issue, you may be right, that the Vtt is the root of why higher Vdimm is needed. You end up raising Vdimm to the point where the "MAX LOW VALUE" on Vtt is high enough for the ram to be happy. That fixing this droop would allow a much LOWER Vdimm for TCCD is likely.

Makes a lot of sense !!

In my case i dont have a doubt that my sys got more and more instable, and as said various times my TCCDs need more and more ram.

Thank to this thread i MIGHT make a conclusion (even as a amateur in those things:) ) that the source of those (my) problems are not the DIMMS itself but has *indeed* to do with that VTT issue. (Inc. VDIMM to lift up VTT <--)

() bad batch of Regulator, board design ? POSSIBLE
But in my case "something" (Regulator ?) seems to get worse....since more and more vdimm is needed.

Q: Is it likely that an voltage regulator "degrades" ? For some reason i see it that if it would be a bad batch then it would stay at a certain "bad" level (ie: instability)....but PROBABLY would not degrade over months (???)

However, the only part i can think of "degrading" over time would be caps, like leakage, which would affect that issue over time.

But then i am only speculating. ALso, AFAIK EMC already concluded its NOT a heat issue etc.

[Tony]

Vdimm mod shocked me quite a bit, ram that needed 2.8V+ at 300fsb now runs well at 2.65v same settings. I will look into VTT and see if the mod helps it along with the booster if i can find the damn leads for the thing ;)

hipro's booster supplies VTT also, so there may be a way of just adding a cleaner VTT to the output leg and see if that gains us some stability...just a theory mind but it does help on the max3 which featured a similar mod i helped develope a while back.

One other alternative would be to tweak the output high for VTT, most dimms will tollerate an overvoltage on VTT its just an under voltage that causes issues, this way we could see a mean VTT value where it should be, high off load and slightly low on load...again just a theory.

[Malves]

Vdimm mod shocked me quite a bit, ram that needed 2.8V+ at 300fsb now runs well at 2.65v same settings.

I'm really glad to hear that, bro.:) Maybe it does something to VTT?

[Tony]

So quick and dirty test before i go to bed, VTT is actually to high on my board and is tracking to a vdimm that is 0.02V higher than it actually is. The vdimm mod had no effect on the droop under load as i saw it with it on and off.

Now my board may be a cherry, i have 3 others here and i will try and hook them up to see if the VTT acts the same on all of them. What we need is an external means of dialing in the VTT, There must be some way of manipulating pin4 to do this.

[EMC2]

Hi Tony... yes there are ways ;) And FYI... adjusting Vtt by POT helps a little... but you can't go much because a) Vtt start off high without load already and b) the droops are too large under some conditions. George's new Maximizer would solve it, but it's a tad high $ for just the needed Vtt solution. If you have multiple MBs... would you be willing to rob one for a RT9173A and parallel a pair to verify it's a pure load condition?

But... why I dropped by tonight was to answer the question as to why it might be a good thing to use the Vmem mod to adjust your memory voltage rather than programming it in the BIOS... at least for Vmem above 3.2V.

Here is what happens during a re-boot of the MB... note it doesn't matter if it's a re-boot initiated within windows, pressing ESC during memtest, or hitting the reset switch... in all cases just after the VGA detect and POST tests, the Vmem regulator takes a drop like this:
http://img207.imageshack.us/img207/6213/vmem3p4vboot1ledannotated4wy.png (http://www.imageshack.us)

This happens with the newer BIOS's that have the "low Vmem during Memory-POST cold boot" fix in them. I don't know about anybody else, but one wouldn't think that would be the best thing in the world. This only occurs if Vmem in the BIOS is set to a voltage greater than 3.2V

Here is a complete picture of what happens during a cold boot now. You can see when the Vmem level is initially set to the value programmed into the BIOS by the user, followed by the same several second dip down to a lower level. You can also see a glitch occuring when that initial level is set:
http://img143.imageshack.us/img143/4510/vmem3p4ventirecoldbootannotate.png (http://www.imageshack.us)

One last note... Vmem (at least on my MB) is 100mV over the value set in the BIOS for the higher voltages ( more than 3.2V using 5V rail).

Have other info collected, but time is up... work tomorrow.

Peace :toast:

[Tony]

A few things we need to be aware of:

All bios files except the one I released apply 0.1V more than what you set in bios if you set TRCD to 2..this was a fix for some corsair dimms that had a few issues. In my bios i had oskar remove it.So if you are looking to test true vdimm you need to install this Bios (http://homepage.ntlworld.com/a.leach80/bios%20files/DFI%20bios%20mods/704-2BT.zip) and remeasure.

Next to get back to my VTT thinking.If we supplied 9173A direct off the 3.3V line and adjusted the pull down circuit so that we could lower the output quite finely this could cure all our issues. At present Vdimm in Vin and voldrop seems to be the issue causing VTT to drop also.TCCD dimms are real power hungery so we may just be seeing to thin traces etc on the board to cope with the load.

So while i know adding a pot onto pin4 would allow a tweak up it would not allow a tweak down, so we need to mod the atcual circuit dictating the 1/2 divide on the output to allow us to work from 1.25V all the way up to 3.2v.

[OSKAR_WU]

Here is what happens during a re-boot of the MB... note it doesn't matter if it's a re-boot initiated within windows, pressing ESC during memtest, or hitting the reset switch... in all cases just after the VGA detect and POST tests, the Vmem regulator takes a drop like this:


This is the problem of bios that reset 3.3V above dram voltage control pin back to default before program 3.3V above voltage and cause the dram voltage lower down below 3.3V ... If the system is not hang up during this time period , it's ok ... 7/04 bios can shorten this time period to be within 10ms ... During this voltage transition period , the bios code will not running until the voltage transition is completed and prevent the system from hang up ...

[OSKAR_WU]

I agree... based on the spec for the RT9173A it should not change that much if max load current is 2A. If it is 2A then... bad batch of RT9173A's? Or maybe because VCtrl = Vin instead of VCtrl > Vin. The spec'd output variation is with Vctrl=3.3V, Vin=2.5V.

Note: Not a temp issue either... 120mm fan over DIMMs and covering Vtt/Vmem regulator area... Vtt regulator is cool to the touch.

Connect Control voltage tab to 3.3V will help a little bit ... But after ddr voltage exceed 3.3V , it will perform worse than connect control voltage tab to DDR voltage ...

Control Voltage=DDR voltage
http://oskarwu.myweb.hinet.net/VDDRCNTROL.GIF

Control Voltage=3.3V voltage
http://oskarwu.myweb.hinet.net/3V3CONTROL.GIF

Original RT9173A performance ...
http://oskarwu.myweb.hinet.net/RT9173A.GIF

[EMC2]

Connect Control voltage tab to 3.3V will help a little bit ... But after ddr voltage exceed 3.3V , it will perform worse than connect control voltage tab to DDR voltage ...
Yes, a problem with higher Vmem if you used the 3.3V rail... you could use either the Vmem regulator's first stage output (you said it was limitted to ~4.2V) or the 5V rail.
Spec allows for up to 6V on Vctrl:
http://xtremesystems.org/forums/attachment.php?attachmentid=33770&stc=1

If you go back and look at the scope shots in post #47, the "regular" drops are 60mV from the nominal center condition, which is 2x the spec'd 30mV as shown in the transient response ratings for the RT9173A.

But the bigger Q is why the 200mV+ drops like shown in post #62 under some operating conditions? Looks like either current limitting is kicking in or the RT9173A is going unstable...

[EMC2]

This is the problem of bios that reset 3.3V above dram voltage control pin back to default before program 3.3V above voltage and cause the dram voltage lower down below 3.3V ... If the system is not hang up during this time period , it's ok ... 7/04 bios can shorten this time period to be within 10ms ... During this voltage transition period , the bios code will not running until the voltage transition is completed and prevent the system from hang up ...

The first dip that occurs during a cold boot is ~10mS long, seen in the 2nd pic in post #117 at the Trigger point. That's where you program the higher Vmem from the minimum level before starting memory detect/post. Here's a zoom in of that area:
http://xtremesystems.org/forums/attachment.php?attachmentid=33773&stc=1

But why the second drop down to 2.7V? Vmem was already properly set to the level set in the BIOS back at the first point and the complete POST has been run at that level. Why not leave it set as it already was? Particularly when the second time there is an overshoot of almost 200mV...and when noise is added on top of that you get this (note BW for Channel 4 is opened up to 250MHz in this pic):
http://xtremesystems.org/forums/attachment.php?attachmentid=33774&stc=1

[EMC2]

A few things we need to be aware of:

All bios files except the one I released apply 0.1V more than what you set in bios if you set TRCD to 2..this was a fix for some corsair dimms that had a few issues. In my bios i had oskar remove it.So if you are looking to test true vdimm you need to install this Bios (http://homepage.ntlworld.com/a.leach80/bios%20files/DFI%20bios%20mods/704-2BT.zip) and remeasure.

Next to get back to my VTT thinking.If we supplied 9173A direct off the 3.3V line and adjusted the pull down circuit so that we could lower the output quite finely this could cure all our issues. At present Vdimm in Vin and voldrop seems to be the issue causing VTT to drop also.TCCD dimms are real power hungery so we may just be seeing to thin traces etc on the board to cope with the load.

So while i know adding a pot onto pin4 would allow a tweak up it would not allow a tweak down, so we need to mod the atcual circuit dictating the 1/2 divide on the output to allow us to work from 1.25V all the way up to 3.2v.
Thanks for the BIOS Tony, but I measure true Vmem ;) And yes, noticed the 0.1V discrepancy...

If you go back and look at the scope pics of Vtt in post #62, you'll see that Vmem doesn't droop at all even under the worst case (200mV) Vtt droop conditions. You can look at the 2nd pic in post #95, which has Vref in it and see that it doesn't droop either (this also shows Vmem isn't drooping since Vref is a simple resistor divider between the pairs of DIMM slots).

Further data point... I looked at Vtt using UTT (CH5) memory last night... Vtt still drops the exact same way and by the same amount. You can see a sample in this thread about 3.3V input levels needed (http://xtremesystems.org/forums/showthread.php?t=68114), in the first pic where Vmem was set to 3.0V with the 3.32V input rail ;)

Regarding the POT... you can tweak up and down... just have to use all 3 legs ;) But again a POT doesn't solve the issue of the large scale changes I've seen. IF it is a Vtt-based load condition causing the droops, it is going to require either an amp-based control circuit to feed the Vref input (pin 4) of the RT9173A so you have dynamic feedback to hold Vtt under control or the addition of a) a second RT9173A in parallel to help handle the load or b) a replacement Vtt circuit that can supply the required current (a couple of possibilities come to mind).

Peace :toast:

[OSKAR_WU]

Yes, a problem with higher Vmem if you used the 3.3V rail... you could use either the Vmem regulator's first stage output (you said it was limitted to ~4.2V) or the 5V rail.
Spec allows for up to 6V on Vctrl:
http://xtremesystems.org/forums/attachment.php?attachmentid=33770&stc=1

If you go back and look at the scope shots in post #47, the "regular" drops are 60mV from the nominal center condition, which is 2x the spec'd 30mV as shown in the transient response ratings for the RT9173A.

But the bigger Q is why the 200mV+ drops like shown in post #62 under some operating conditions? Looks like either current limitting is kicking in or the RT9173A is going unstable...

1 . Use 5V is not recommend by richtek in recent batch of regulator ... Using 4V is one thing that can be consider ...

2 . The nominal center of actual board is different from dummy load testing like the richtek datasheet ... The patter in memtest8# already cover the full current sinking/sourcing mode of this regulator , I will only check the peak-to-peak range of the result of actual board ...

3 . 94mv in my original measurement is not very good , but acceptable when you consider that the VTT is 1.45V but not 1.25V in the richtek datasheet ... And this is the TCCD/300MHz/1T case , if the DRAM is BH5/CH5 type or the DRAM frequency is much lower , the value will be smaller ...

4 . I don't know what happened to your board , but I have tried 4 different board(different batch/model) ... All of them act very close to the pic I post ...

[OSKAR_WU]

The first dip that occurs during a cold boot is ~10mS long, seen in the 2nd pic in post #117 at the Trigger point. That's where you program the higher Vmem from the minimum level before starting memory detect/post. Here's a zoom in of that area:

But why the second drop down to 2.7V? Vmem was already properly set to the level set in the BIOS back at the first point and the complete POST has been run at that level. Why not leave it set as it already was? Particularly when the second time there is an overshoot of almost 200mV...and when noise is added on top of that you get this (note BW for Channel 4 is opened up to 250MHz in this pic):


I don't know if you test this with 7/04 bios ... With 7/04 bios , the period should be within 10ms in the 1st stage and 2nd stage ... I can not explain the detail of all the bios programming voltage transition limitation , it's a protection behavior I set ...

[flexy]

i hope people *here* dont confuse the VTT droop with the VDIMM droop when VDIMM is close to 3.3 rail ? :) I know they confuse those two issues elsewhere.
VTT droop also occurs with LOWER VDIMM (eg. 2,8 or 2,9) where VDIMM is NOT fluctuating at all.

The "VDIMM fluctuates" is a different story than "VTT droops".

VTT drop: Occurs ALWAYS (?) no matter what VDIMM is at and what rail you grab your vdimm off.

VDIMM drop: Occurs if your VDIMM is too close to your 3,3 rail...eg. starts here once i set VDIMM to 3.0, gets really bad at 3.1 (like EMC showed yesterday)

[Tony]

I have modded an A00 with vdimm and VTT;) i will see what effect this has if any on overclocking etc.

[uwackme]

You could use a diode to connect the 5V rail to the Vcontrol input, as this will lead to a .7v DROP in the voltage at the pin...4.3V.

Keep the leads as short as possible. Dont use long leads on things, they act as antenna's to add noise into the circuit.

[EMC2]

1 . Use 5V is not recommend by richtek in recent batch of regulator ... Using 4V is one thing that can be consider ...

2 . The nominal center of actual board is different from dummy load testing like the richtek datasheet ... The patter in memtest8# already cover the full current sinking/sourcing mode of this regulator , I will only check the peak-to-peak range of the result of actual board ...

3 . 94mv in my original measurement is not very good , but acceptable when you consider that the VTT is 1.45V but not 1.25V in the richtek datasheet ... And this is the TCCD/300MHz/1T case , if the DRAM is BH5/CH5 type or the DRAM frequency is much lower , the value will be smaller ...

4 . I don't know what happened to your board , but I have tried 4 different board(different batch/model) ... All of them act very close to the pic I post ...

1. I noticed the note for the ACL5 part, but you aren't using that version are you? And yes... 4V should be fine since Vmem can reach 4V and is thus already used...

RT9173 Discussion picture:
http://img221.imageshack.us/img221/4796/rt9173abreakdown9ij.png (http://www.imageshack.us)

2. Yes, the nominal center of the actual board may be different, but it still exists... and the Vtt still goes in one direction due to sourcing current and the other direction due to sinking current... nothing to due with the MB will change that. Looking only at the peak-to-peak variation is misleading... and doesn't take into account assymetrical loading issues. The nominal center by design of the part is Vref+Vos. You can either use Vref as nominal or Vtt @ minimal/zero load. It's pretty obvious when looking at what Vtt does under testing that it does have a real and measurable center position. One example would be it's value during Memtest T5, where it stays rock solid and equal to Vref... another would be with Memtest paused, where you see an apparent small Vos in the positive direction.

3. No it isn't very good... especially when assymetry is taken into account. Regarding the 1.45V versus 1.25V - as shown in the discussion pic I put together from RichTek's spec, the variation of Vtt is almost purely a function of load current, not Vtt level, as can be seen and is annotated in the pic. That's also why the % delta for DDR1 is less than for DDR2. Note that the 3A delta is right at 2X the 1.5A delta as well. From my testing to date, this is confirmed, as I see no appreciable difference due to the level of Vtt/Vmem.

Regarding whether it is related to TCCD or 300Mhz or frequency in general, here's some captures using CH5 based DIMMs at two different frequencies (and lower than the TCCD captures). Note that these were both taken with everything EXCEPT the memory speed kept constant.

240Mhz UUT Memtest T8:
http://img301.imageshack.us/img301/3623/240muttt8annotated2tg.png (http://www.imageshack.us)

120Mhz UTT Memtest T8:
http://img139.imageshack.us/img139/8191/120muttt8annotated0wn.png (http://www.imageshack.us)

You'll notice that the Vtt magnitude change remains the same between 240Mhz and 120Mhz MemClock... and right at the same as what was seen with the TCCD at 300Mhz.

4. I don't think it's just my MB... but since I've used 2 different PSs, 3 different CPUs, and 3 different sets of memory of 2 different kinds, it is restricted to the MB in general.

I do think you aren't seeing the very large changes that I've recorded because of test condition and equipment differences most likely. Two questions come to mind after further testing tonight...

a) have you used the test conditions in Windows that I sent you the info on?
b) have you run those test conditions with a Winnie rather than an FX?
c) what Vcore levels have you done testing with, just default or higher?


I did go back this evening and also re-checked the "large step" conditions I had previously seen in windows, this timing using 2x512MB of CH5 based DIMMs. The first run I did not see the magnitude of change I had previously. So... I sat down and analyzed all the differences between the two sets of runs.

a) CH5 versus TCCD
b) 200Mhz FSB vs 295Mhz FSB
c) 200Mhz MemClock vs 295Mhz MemClock
d) Vmem 3.3V versus 2.9V

Everything else was exactly the same (ok... temp might be +/-2C different)... including external test equipment, probe points, etc.

So I decided I would eliminate the differences I could easily, one at a time. First thing I did was go into the BIOS, set the FSB back to 295Mhz, dialed in a memory ratio of 4/5 to keep the UTT speed down, and re-ran the test.

Here is 295x9:
http://img139.imageshack.us/img139/8711/winmt295x9annotated0vv.png (http://www.imageshack.us)

Bingo - we have the problem showing up again. Now, was it the higher frequency on the memory or on the CPU. So I made a series of 3 more runs, each one with everything EXCEPT the CPU multiplier the same:

295x8 Win MemTest:
http://img139.imageshack.us/img139/4623/winmt295x8annotated0fn.png (http://www.imageshack.us)

295x7 Win MemTest:
http://img139.imageshack.us/img139/8205/winmt295x7annotated9ly.png (http://www.imageshack.us)

295x6 Win MemTest:
http://img139.imageshack.us/img139/4210/winmt295x6annotated6ba.png (http://www.imageshack.us)

The last run (295x6) is very close to the first unrecorded run (scope trigger set too low, looking for a bigger droop) where setup was 200x9, 1:1 on memory. Note how the magnitude of the change goes down each time.

This actually makes some degree of sense... one big thing in common with the majority of conditions under which the large scale (>100mV) droops occur are when the CPU and memory utilization rate changes by a large amount and the speeds are relatively high.

The only other condition to date that I've seen cause the large magnitude droop on Vtt is the video switchover that occurs during Win2K bootup... but it is another potential large scale current demand change on the MB and full-bore utilization to low utilization...

It appears now one of two things are going on with the large scale droops - either the regulator is loosing it (stability) do to power demand changes or there is some condition where we get a higher than expected load demand on Vtt due to some unforeseen combination and the regulator's overcurrent circuit is tripping.

I don't know if you test this with 7/04 bios ... With 7/04 bios , the period should be within 10ms in the 1st stage and 2nd stage ... I can not explain the detail of all the bios programming voltage transition limitation , it's a protection behavior I set ...

I did that testing with 510fixed BIOS. I haven't looked at it yet with 7/04, but I will. Hopefully the shorter duration/method prevents the overshoot I saw (if not may need to raise it halfway, pause, then the rest of the way).

I can not explain the detail of all the bios programming voltage transition limitation , it's a protection behavior I set ...

hmmmmmm... this "protection behavior" occurs at the same relative time as when the Video is re-initialized (right after VGA detect/POST) and when video modes are changing (my test bed monitor makes a distinct, audible 'click' when video modes are changed)... one of the conditions that I've seen the large scale Vtt fluctuations is during the Windows initialization of the video and video mode change... related perhaps?

Peace :toast:

[EMC2]

I have modded an A00 with vdimm and VTT;) i will see what effect this has if any on overclocking etc.
Curious which Vtt mod you decided to try out... and look forward to your efforts :)

--- uwackme ---
Just FYI... Vctrl is a :banana: to change... it's on the TAB of the part, so the part has to be totally removed and isolated (plus HS), then put back down to connect up the other 4 pins to make a Vctrl mod :( Someone want to give me a mod-mule MB to use tho...

[suio]

EMC2 and OSKAR,

I noticed the same voltage behavior with OCZ PC3200 Gold BH-5 (OCZ4001024ELDCGE-K) memory a while back. I no longer see such issue exists with the OCZ Plat. Rev2 TCCD memory. I even posted the question at DFI-Street forum about a week ago. No one responded of course.

P.S. My video card is acting strangely (BSOD every 2-3 hours) in recent days. Any possibility the NF4 Ultra-D board could do something to the video card?

[alpha0ne]

EMC2 and OSKAR,

I noticed the same voltage behavior with OCZ PC3200 Gold BH-5 (OCZ4001024ELDCGE-K) memory a while back. I no longer see such issue exists with the OCZ Plat. Rev2 TCCD memory. I even posted the question at DFI-Street forum about a week ago. No one responded of course.

P.S. My video card is acting strangely (BSOD every 2-3 hours) in recent days. Any possibility the NF4 Ultra-D board could do something to the video card?

On two occasions after changing bios upto the 704 then restarting after reconfigure (I have done this on hundreds of boards/chipsets/CPU's so no stranger :) ) I have noticed SEVERE screen corruption that looks like the graphics card (X800) is being either overvolted or the pci-e bus is wayyy over speed

I have only ever come across such behaviour in the past when I have overvolted due to modding a vid card done back in my 8500 days :confused:

[flexy]

nice job by you guys measuring and all that :)

Btw. do we have that vtt issue no matter what DIMM slots we use and if it's related to load created by the DIMMs, and do we get smaller drops by using eg. only one dimm ?
Just wondering.

[groovetek]

Well I certainly haven't studied enough electronics yet to analyse and comment on the graphs and technical explanatios above, but a question to Oskar Wu and/or EMC2:

My CPU died the second I pressed save settings and exit in the 704-2 BIOS. I had changed VID to 1.200, VID special to *133%. This is a setting I had used in previous BIOS's and found gave me the optimal VCORE for my Venice 3000+ 0517 EPMW. The BIOS would read 1.56V, which was perfect for allowing 3ghz prime/bench/stressCPU stable on air cooling.

Now, of course you would understand that I am very frustrated with losing such an amazing chip, and naturally that I would point my finger at the BIOS, so it would be great if knowledgeable people like you could look into the issue and see if the BIOS did introduce some voltage control problem.

I have tested the RAM and graphic card, both are working fine in my friend's system, and my CPU is confirmed to be dead. No power even runs through the chip, since no heat is being generated at all.

I haven't yet tested the DFI NF4 Ultra-D board with another CPU yet, despite having thoroughly resetted the CMOS. I am very apprehensive about sticking another CPU into this board, especially with the 704-2 BIOS still in it. My response from DFI technical support was to RMA the board, and that there may indeed be something wrong with the BIOS... but that's all I've heard, and I've sent an in-depth email regarding the symptoms, to see if they can take the information and use it constructively to debug or verify the 704-2 BIOS, and let me know if the BIOS was at fault or if it was the board, or if (unlikely) it was just something else or some freak incident. I haven't had a response for days, but that's OK, I'm a patient person. I have ordered an Abit AN8 though... don't want to potentially risk other hardware.

This was the original response from DFI after I had briefy explained my problem:
_____________________________
Dear Customer

Thanks for your letter of July 06. According to your problem description, there might be something wrong with BIOS. Please contact with your retailer and apply for RMA service. I apologize for the inconvenience may cause you.

Sincerely Yours truly,

Tech Support

DFI Inc.

Issue NBR: (~~~~snip~~~~)
___________________________

So this is the reply I made, and seeing as there are many knowledgeable people here - maybe you can take it in and see something that makes sense... I'm no electrical engineer yet, so my theories and stuff can be radically impossible, so please take that into consideration. I do however, have alot of experience with hardware, and have been overclocking for a very long time.

___________________
Hello DFI,
Thankyou for the reply. Unfortunately after extensive testing and debugging of various components in my system today I have found that my Venice CPU has died, most likely as a result of a bug in this 704-2 BIOS (Oskar Wu, Hellfire, Merlin version).

I believe the VID control may have a bug, allowing the board to spike the voltage when using certain VID & VID special settings. I believe this is the reason, because usually the commonly experienced symptom of constant over-voltage (typically around >1.75v for 0.09u A64 CPUs) is that the CPU is gradually damaged due to electron migration, however in my case the CPU instantly lost power after saving settings and exitting. The VID selected was 1.200 with VID special control of 133%, which I have used previously with other BIOS's to achieve a 1.56vcore BIOS reading, far below the maximum tolerance of such A64 chips, especially when temperature was well under control. I have also observed that there is literally no electricity running through the CPU (CPU is generating no heat at all, motherboard showing 4 diagnostic LEDs, usually indicating CPU is not even being detected), and to me this sounds like a blown trace or maybe a blown surface-mounted component - which usually would not occur unless a suddenly excessive high voltage is applied. Therefore, I believe the BIOS caused the motherboard to suddenly apply the max vcore that can be supplied immediately after I saved settings and exitted BIOS. I am concerned that other people may be affected, and so I think it's important that Oskar Wu, or whoever is the head of the DFI BIOS development team to be notified of the possibility of the presence of a bug in this BIOS. Again I have to emphasize that I cannot be 100% positive that the BIOS is at fault, but logically it seems to be the case.

Therefore, I speculate that the motherboard itself may still be functional - however I will not know until my new CPUs arrive. But as you would understand, I'm feeling VERY apprehensive and worried about testing my new CPUs on a board that is potentially dangerous. I do not want any more CPUs to be possibly destroyed by the board, even though I have resetted the CMOS - I still cannot feel secure about this. And yet on the other hand, if I apply for RMA with the board and they say there is no problem with it, then it would have been a big waste of time, and also money.

What is your suggestion to be the best solution to my situation? And, typically, under such circumstances, would AMD's RMA system cover the death of my Venice 3000+ CPU if it was caused by the motherboard? I understand that overclocking is not covered by CPU manufacturers, but in such a case, the death is most likely (as I stated before, I cannot be 100% positive) not directly to do with overclocking, but motherboard/BIOS related. Indeed, as you said, this has caused a large inconvenience for me, not only because I have go to through this RMA process, but mainly because I have lost a truly special CPU.

Any constructive help would be greatly appreciated, thankyou very much for your consideration thus far.

Kindest Regards,
John.
__________________

Any help would be GREATLY appreciated guys!

[timpanogos]

groove, fwiw ... I found that messing around with the various vcore settings can be very touchy ... I also work for low vcore with high multiplier, but that 1.20/133% was a no poster for me. try to stay in the 1.30 to 1.35 ranges with various multipliers..

however, a vcore conversation here is the wrong place ... this is a very import thread to many and we should try to keep this focused on vtt/vdimm issues at this point.

you should post support issues to dfi-street or start a different thread at this site.

just my 2cents

[Malves]

Didn't read the long post about the vcore. Anyways, for better vcore control, just do this vcore mod (http://www.malvescorner.net/dfinf4.html).

[Ubermann]

On two occasions after changing bios upto the 704 then restarting after reconfigure (I have done this on hundreds of boards/chipsets/CPU's so no stranger :) ) I have noticed SEVERE screen corruption that looks like the graphics card (X800) is being either overvolted or the pci-e bus is wayyy over speed

I have only ever come across such behaviour in the past when I have overvolted due to modding a vid card done back in my 8500 days :confused:

I have seen the same thing, it looks like a voltmod that has gone bad but when you reboot its back to normal.
But this was with an older bios and an untouched X850 card.
But you get eyes big as an octopus and heart stops beating when you see it.

[wtz54321]

Well I certainly haven't studied enough electronics yet to analyse and comment on the graphs and technical explanatios above, but a question to Oskar Wu and/or EMC2:

My CPU died the second I pressed save settings and exit in the 704-2 BIOS. I had changed VID to 1.200, VID special to *133%. This is a setting I had used in previous BIOS's and found gave me the optimal VCORE for my Venice 3000+ 0517 EPMW. The BIOS would read 1.56V, which was perfect for allowing 3ghz prime/bench/stressCPU stable on air cooling.

As far as I know , this is beta bios ... And anything that screw up things could be happened ... You should not use it if you are ok with previous bios ...

[groovetek]

yes, well, previous bios's had issues with async overclocking with my G.Skill UTT BH5 GH kit.

it looks like at dfi-street, someone has killed their FX55 sandiego the exact same way with this BIOS... maybe it's coincidence that it's with a 704 BIOS as well, but me thinks otherwise.

[alpha0ne]

Well the official 310 bios is even worse. I lost my first pair of RAM with it.

IMHO the err 'official' 310 bios is a 'kin disgrace :rolleyes:

[groovetek]

i think the weird graphics corruption thing could be indirectly related to more voltage controlling bugs that could potentially be present with this BIOS.

[wtz54321]

yes, well, previous bios's had issues with async overclocking with my G.Skill UTT BH5 GH kit.

it looks like at dfi-street, someone has killed their FX55 sandiego the exact same way with this BIOS... maybe it's coincidence that it's with a 704 BIOS as well, but me thinks otherwise.

I don't see any information that 7/04 bios solve the async issue ... So before you update to a bios that is still beta , you should know that could be happened , especially when there is unknow amount of ppl does not have any problem with the beta bios ...

[tictac]

Well I certainly haven't studied enough electronics yet to analyse and comment on the graphs and technical explanatios above, but a question to Oskar Wu and/or EMC2:

My CPU died the second I pressed save settings and exit in the 704-2 BIOS. I had changed VID to 1.200, VID special to *133%. This is a setting I had used in previous BIOS's and found gave me the optimal VCORE for my Venice 3000+ 0517 EPMW. The BIOS would read 1.56V, which was perfect for allowing 3ghz prime/bench/stressCPU stable on air cooling.

Now, of course you would understand that I am very frustrated with losing such an amazing chip, and naturally that I would point my finger at the BIOS, so it would be great if knowledgeable people like you could look into the issue and see if the BIOS did introduce some voltage control problem.

I have tested the RAM and graphic card, both are working fine in my friend's system, and my CPU is confirmed to be dead. No power even runs through the chip, since no heat is being generated at all.

I haven't yet tested the DFI NF4 Ultra-D board with another CPU yet, despite having thoroughly resetted the CMOS. I am very apprehensive about sticking another CPU into this board, especially with the 704-2 BIOS still in it. My response from DFI technical support was to RMA the board, and that there may indeed be something wrong with the BIOS... but that's all I've heard, and I've sent an in-depth email regarding the symptoms, to see if they can take the information and use it constructively to debug or verify the 704-2 BIOS, and let me know if the BIOS was at fault or if it was the board, or if (unlikely) it was just something else or some freak incident. I haven't had a response for days, but that's OK, I'm a patient person. I have ordered an Abit AN8 though... don't want to potentially risk other hardware.

This was the original response from DFI after I had briefy explained my problem:
_____________________________
Dear Customer

Thanks for your letter of July 06. According to your problem description, there might be something wrong with BIOS. Please contact with your retailer and apply for RMA service. I apologize for the inconvenience may cause you.

Sincerely Yours truly,

Tech Support

DFI Inc.

Issue NBR: (~~~~snip~~~~)
___________________________

So this is the reply I made, and seeing as there are many knowledgeable people here - maybe you can take it in and see something that makes sense... I'm no electrical engineer yet, so my theories and stuff can be radically impossible, so please take that into consideration. I do however, have alot of experience with hardware, and have been overclocking for a very long time.

___________________
Hello DFI,
Thankyou for the reply. Unfortunately after extensive testing and debugging of various components in my system today I have found that my Venice CPU has died, most likely as a result of a bug in this 704-2 BIOS (Oskar Wu, Hellfire, Merlin version).

I believe the VID control may have a bug, allowing the board to spike the voltage when using certain VID & VID special settings. I believe this is the reason, because usually the commonly experienced symptom of constant over-voltage (typically around >1.75v for 0.09u A64 CPUs) is that the CPU is gradually damaged due to electron migration, however in my case the CPU instantly lost power after saving settings and exitting. The VID selected was 1.200 with VID special control of 133%, which I have used previously with other BIOS's to achieve a 1.56vcore BIOS reading, far below the maximum tolerance of such A64 chips, especially when temperature was well under control. I have also observed that there is literally no electricity running through the CPU (CPU is generating no heat at all, motherboard showing 4 diagnostic LEDs, usually indicating CPU is not even being detected), and to me this sounds like a blown trace or maybe a blown surface-mounted component - which usually would not occur unless a suddenly excessive high voltage is applied. Therefore, I believe the BIOS caused the motherboard to suddenly apply the max vcore that can be supplied immediately after I saved settings and exitted BIOS. I am concerned that other people may be affected, and so I think it's important that Oskar Wu, or whoever is the head of the DFI BIOS development team to be notified of the possibility of the presence of a bug in this BIOS. Again I have to emphasize that I cannot be 100% positive that the BIOS is at fault, but logically it seems to be the case.

Therefore, I speculate that the motherboard itself may still be functional - however I will not know until my new CPUs arrive. But as you would understand, I'm feeling VERY apprehensive and worried about testing my new CPUs on a board that is potentially dangerous. I do not want any more CPUs to be possibly destroyed by the board, even though I have resetted the CMOS - I still cannot feel secure about this. And yet on the other hand, if I apply for RMA with the board and they say there is no problem with it, then it would have been a big waste of time, and also money.

What is your suggestion to be the best solution to my situation? And, typically, under such circumstances, would AMD's RMA system cover the death of my Venice 3000+ CPU if it was caused by the motherboard? I understand that overclocking is not covered by CPU manufacturers, but in such a case, the death is most likely (as I stated before, I cannot be 100% positive) not directly to do with overclocking, but motherboard/BIOS related. Indeed, as you said, this has caused a large inconvenience for me, not only because I have go to through this RMA process, but mainly because I have lost a truly special CPU.

Any constructive help would be greatly appreciated, thankyou very much for your consideration thus far.

Kindest Regards,
John.
__________________

Any help would be GREATLY appreciated guys!

Maybe here is the reason why...
http://www.dfi-street.com/forum/showpost.php?p=159120&postcount=1

[alpha0ne]

Maybe here is the reason why...
http://www.dfi-street.com/forum/showpost.php?p=159120&postcount=1

FARRRK me Oscar should have posted that HERE 2 days ago, not everyone relies on DFI street as the font of knowledge, MANY more do HERE :(

[EMC2]

Give Oskar a break... I seriously doubt he knew it two days ago... I'm sure he posted on "the street" as soon as he found it... and word got from "the street" to hear in a matter of hours (look in AMD section).

Oskar is by far the most responsive MB company engineer around and has busted his chops for the enthusiast community for quite a number of years. Sheesh....

/rant off

Peace :toast:

[THunDA]

Not to mention you always take a chance when flashing a beta bios.. Im sure Oscar will have it sorted out soon..

[bachus_anonym]

Yep... Beta, just like Alpha BIOS should be flashed ***ONLY*** if one has issues with previous, Official BIOS.
Unfortunately, this might mean that even though BIOS glitch might have killed your chip, you're probably out of luck. Unless, DFI will be certain that that was the reason for it's death, then it would not really kill them to get you a new chip... It would be pretty good PR to me... Showing how much they care for users "beta-testing" their BIOSes.

Anyway, just take it easy. Don't attack Oscar Wu for that... get in touch with them one more time and see if they can help you with possible replacement or sth...

[groovetek]

I haven't and have no intention of attacking him or even DFI at all - In fact I admire Oskar Wu for his honesty and willingness/commitment to solve the problem. I have, however, tried my best to warn other DFI nf4 users of the bug in the BIOS. I've been very rational with my emails and posts as you can see here on XS, and also on dfi-street, i4memory.
That said, I am confused how a BIOS could introduce such a fatal bug though, even if it is an alpha... I don't know how to code/program BIOS's, but assuming the code for VID doesn't change from 1 bios to another (since that's not where improvements are required/or being changed), it's surprising that this can occur...

I only used the 704 BIOS because every BIOS before that was giving me troubles with G.Skill GH BH UTT kit when using async memory divider settings. I had followed every guide, tried dozens of different settings, all with no proper stability. The 704 finally did it for me and I was very happy, but then unfortunately, this happened, when deciding to up my CPU speed (i need 1.56v (1.20 * 133%, tested in prevoius BIOS's) for 3.0ghz, it was set to 1.525v and no "Above VID %" setting prior to this)...

As for getting me a new chip - it would be good PR for DFI, but unfortunately it wouldn't happen with a large-scale manufacturer like DFI because they are already popular enough as it is... and where would they find me another week 17 chip that goes as hard as mine did, haha... I'd love to find another one that could though... sigh... :( not to mention as a uni student with no proper job atm, the cost of computer hardware really adds up. I had waited 3 months to build this system after selling my old parts because of exams and because I knew winchesters and AGP platform-related parts would lose value very soon after that, so sacrificed all this time so I could gather enough money for these parts, and then on the 3rd day of setting it up it dies on me, very very bad luck :slapass: .

edit: if anything though - it seems at least here in Australia, AMD's RMA system is extremely stringent, and I may not be able to get a replacement under these circumstances... if that is the case, then it'd be good if i did get just any 3000+ replaced for me... although do undrestand that DFI is not obliged to do this, since it was an alpha BIOS...

[stealth17]

[on topic]

i did the vdimm mod the other day but located the pot down neat the chipset. this means i have the wires about 6inches long that goto pin 4 and 6. now that i think about it though, is that a bad idea? wouldnt i be introducing a lot of EMI and loss?

thanks

[/on topic]

[CaTalyst.X]

You can reduce some EMI by wrapping the GND wire around the Hot wire for as far as you can until you get to the solder points. You could glue the pot to the FET Heatsink thats right next to LM358 if you want to feel safer.

-CaT

[Tony]

So i have had a few mails asking about the mods I did. i know Malves has already posted but these still may help someone for the Vdimm. i have added the VTT also with the connections explained.

VTT:
http://homepage.ntlworld.com/a.leach80/DFI%20NF4%20vdimm/VTT-DFI.JPG

Vdimm:
http://homepage.ntlworld.com/a.leach80/DFI%20NF4%20vdimm/Vdimm-dfi.JPG

VTT is worth it IMO, i was able to gain a few fsb at 2.65V 300fsb+ and it did seem more stable, the pot swings the voltage either way.

[timpanogos]

any suggestions on how to tweak these two and there interactions? For example, I assume set the vdimm mod first, and then tweak the vtt mod to be 1/2 of vdimm?

Is that the idea?


any measuring points on the vtt mod better than others??
Thanks!!

[Tony]

any suggestions on how to tweak these two and there interactions? For example, I assume set the vdimm mod first, and then tweak the vtt mod to be 1/2 of vdimm?

Is that the idea?


Any measuring points on the vtt mod better than others??
Thanks!! measure VTT on the 9173A, I just set Vdimm slowly and tweak VTT along with it. The dip is still there, but I was able to tweak VTT a little high, this reduced ther dip and gained stability.

next mod is to add another 9173 and see if the dip is reduced even further...all i have to do is find a source for the chip.

I was supprised to see how little Vdimm is actually really needed, 2.75V or so on a few dimms and usually 2.65 to 2.68V max's the dimms out.

[flexy]

hey bigtoe, thanks, very interested in the VTT mod. How much better is the VTT fluctuations with only this mod ? Or should we wait 'til we have some more info regarding a mod with maybe another 9173A ? I really want to totally eliminate those VTT fluctuations.

Regarding the mod: might it be possible that, instead of soldering to an R there is a pin right on the DIMM slot, some PIN where we can do that instead of the need to solder around on that resistor ? Just wondering

[EMC2]

--- Flexy --- Pin 1 & Pin 7 of the DIMM slots (Vref & Vdd respectively)... will go right down into the test point clips of the DIMM socket... this would allow you to raise Vtt only, no lowering (which you don't really want anyway). From my previous testing, doesn't change magnitude of the dips, only offsets them so absolute value isn't so low. Or use 1, 93, & 96 for up/down control (Vref, Gnd, VddQ respectively). Center leg of POT to pin 1 (Vref), outside leg(s) to other pin(s).

--- Tony --- Only place I've found any RT9173As was a distributor in NY stateside... and they had a minimum order of 100 :/ Just rob one off one of your other MBs :p:

[timpanogos]

ouch on the min order!

[felinusz]

I have two questions for you folks :)

My 50K VRs (I ran out :() should be here tomorrow, I'm going to install VTT and VDIMM voltmods on my board when they do get here.


~ How hot can VTT be run,without compromising stability?

~ Is a hot VTT better than a low VTT for stability?

~ At what point does an above-reference VTT begin to adversely affect stability?

~ When you say "10K OHm VR set to midpoint", you mean 5K of resistance right?

Thanks, I'll be sure to share my results!

[craig588]

I just found something which brings all sorts of ridiculous ideas to mind, a 2 farad capacitor pack that came out of a dead power amp. It's like the size of a car battery, but if it has the potential to fix these VTT problems I would love to waste it on a motherboard. What points should I try attaching it to? (No rush, I'm out a videocard right now because of neweggs crappy refurb sales, at least they have a good RMA service)

[Tony]

I have two questions for you folks :