ok..i KNEW i am not alone :)Quote:
Originally Posted by EMC2
Btw. so it looks like the OCZ booster may fix this ?????
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ok..i KNEW i am not alone :)Quote:
Originally Posted by EMC2
Btw. so it looks like the OCZ booster may fix this ?????
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
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...Quote:
Originally Posted by flexy
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
tony at ocz did a simple vdimm mod
http://www.bleedinedge.com/forum/sho...80&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.Quote:
Originally Posted by flexy
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
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.
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.
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).
Yes, it is the same vdimm mod. Pin 4 that I use is ground. Really doesn't matter what ground you use.Quote:
Originally Posted by stealth17
Hey EMC2,
Maybe it's time to test the board on the scope with the vdimm mod.
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.
Makes a lot of sense !!Quote:
Originally Posted by uwackme
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.
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.
I'm really glad to hear that, bro.:) Maybe it does something to VTT?Quote:
Originally Posted by bigtoe
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.
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/img207/6...notated4wy.png
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/img143/4...otannotate.png
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:
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 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.
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 ...Quote:
Originally Posted by 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 ...Quote:
Originally Posted by EMC2
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
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.Quote:
Originally Posted by OSKAR_WU
Spec allows for up to 6V on Vctrl:
http://xtremesystems.org/forums/atta...id=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...
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:Quote:
Originally Posted by OSKAR_WU
http://xtremesystems.org/forums/atta...id=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/atta...id=33774&stc=1
Thanks for the BIOS Tony, but I measure true Vmem ;) And yes, noticed the 0.1V discrepancy...Quote:
Originally Posted by bigtoe
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, 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:
1 . Use 5V is not recommend by richtek in recent batch of regulator ... Using 4V is one thing that can be consider ...Quote:
Originally Posted by EMC2
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 ...
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 ...Quote:
Originally Posted by EMC2