NF7 rev2 VTT mod need it so bad...

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Originally posted by Rabbi_NZ
Can the people that did the cut-trace method tell me if their Dual N mosfet is getting hot?
Has there been any board deaths because of the cut-trace method yet?

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oh yeah, it is by far the hottest single component on my mobo...(excluding vcore mosfets). measured with temp probe under load at 3.4vdimm and 1.7vtt i get 45C...

still live and kicking, though... i'll be getting dremel kit soon to cut another hole in my side panel so i could mount 120mm fan blowing over mem 'n this mosfet area :D

bachus, have you had any trouble at all with the current flowing thru that Vtt VR?

I know that this is an issue on the IC7 line, so just checking.

Just finished doing the trace cut method, and very happy with the results. But want to make certain that the current isnt going to overwhelm the poor little VR and cause a melt-down.

I tried the "Vref = Vtt" ... a no go for me.

not 100% sure what u mean...
but i was wondering if out of the blue the mosfet got this hot then maybe it has some impact on that pot too... maybe i will measure the temp on it too ;)
i'm not at home right now but i will do that later...
ATM, i'm struggling to get my setup prime stable at 244FSB... i mean it is prime stable but for some reason 6th hour finishes with BSOD... i think it's time to revise my 2.1vdd :D or my mobile can be the one to blame too...

glad u done it too.... i will retest it tommorow but i 'm 95% sure that vtt mod didn't help me much... i will confirm that or not later...

Well, to put it more clear:

On the IC7, to get 1.6v or more on the Vbt, the VR is practically at 0 ohms...it is around 1/2 ohm, which puts the current at a whooping 3.2Amps...oucherz. Those little VRs dont stand a chance against that amount of current.

But, MadCat put together a fix for that...so all is well.

I am not sure what the resistance is on the VR when Vbt is at 1.6v or so..can you check that easily and let me know.

no problem :) i will check that for u tommorow when i get home...

I thought with the cut-trace method once you set the Vtt VR to approx 200ohm it will track a VDimm mod of approx 3.2v max as a 1:2 ratio..?

If I do this with mine (eg, limit vdimm to 3.2v) my VR will never get to 0ohms will it?
So i won't have to worry about the overcurrent issue as much...?
________
Suzuki Katana

Quote:

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Originally posted by Rabbi_NZ
I thought with the cut-trace method once you set the Vtt VR to approx 200ohm it will track a VDimm mod of approx 3.2v max as a 1:2 ratio..?

If I do this with mine (eg, limit vdimm to 3.2v) my VR will never get to 0ohms will it?
So i won't have to worry about the overcurrent issue as much...?

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Actually, you set the VR to zero ohms and increase the resistance to increase the Vbt voltage.

It does not auto-track as far as I am aware..you have to adjust hte VR to the correct resistance to achieve the needed voltage.

As far as i've observed, the Vtt increases the same when you increase the Vdimm automatically.
For example, i did the Vtt with the cut trace method (and 1K resistor), set up the Vdimm to the lowest (2.6v bios) set up my Vdimm resistance to give me 2.90-91v's and the Vtt to 1.46v's.
When i raise the Vdimm to 2.8 (from bios) which is approx. 3.11v, the Vtt is changed automatically without doing anything to 1.56v (half the Vdimm).

Byron

Once done, and set, the Vtt will track Vdimm... but the whole "window" of setting moved from stock bios range...2.6V-2.9V to a new range... 3.0V-3.3V (as set in my case) because of the Vdimm mod.

Within this new range, they track correctly. if I alter the Vdimm pot... I must then also alter Vtt pot, but once set, they track within the new range of bios adjustment.

The circuit the pot is in is a low current feedback loop, no risk of burning the pot up. Set for 3.0-3.3 range, my pot value was 90ohms.

It seems an incovenience, but once you dial in the new range, you wont have to bother touching the pots again....so it isnt really.

Quote:

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Originally posted by bachus_anonym
oh yeah, it is by far the hottest single component on my mobo...(excluding vcore mosfets). measured with temp probe under load at 3.4vdimm and 1.7vtt i get 45C...

still live and kicking, though... i'll be getting dremel kit soon to cut another hole in my side panel so i could mount 120mm fan blowing over mem 'n this mosfet area :D

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Did you do the Cut-Trace method or Vref=Vtt?

Does the MOSFET get hotter with some Vbt Mod methods than with others?
________
vaporizer

i have set up 2.9v in BIOS to be 3.4v in reality. the vtt is set to 1.71v and the resistance is 259 ohm.
lowering vdimm in BIOS or using nf7svcore in steps to 2.6v results in vtt tracking vdimm down in 1/2 correct ratio...
so everything works just fine.
of course it doesn't track down when u change vdimm using pot rather than BIOS or nf7svcore at the same. e.g. 2.9v preset in BIOS.

Yes once you do the cut-trace, the mosfet gets warmer than it had been, but that's only natural, 1.3V to 1.6V is a 20+% boost in the power dissipation. I slapped microcool heatsinks on both mine, no probs since, warm not HOT. Make sure you have air flow over the rams.... my LX-6A19/SLK3700/Superlanboy/D8000 case design has a fraction of intake air moving over the rams, the way the HDisk cage is laid out.

true... that's why i'm ordering dremel kit and 120mm fan to make little modification to my side panel.. yeah, 2x120mm fans that will be ;)

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Originally posted by uwackme
Yes once you do the cut-trace, the mosfet gets warmer than it had been, but that's only natural, 1.3V to 1.6V is a 20+% boost in the power dissipation. I slapped microcool heatsinks on both mine, no probs since, warm not HOT. Make sure you have air flow over the rams.... my LX-6A19/SLK3700/Superlanboy/D8000 case design has a fraction of intake air moving over the rams, the way the HDisk cage is laid out.

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Here's my setup...

Antec SuperLanboy - modified to have a 120mm Blowhole exhaust aswell.
Bottom front (120mm) blows in, top back (120mm) blows in through radiator, top blowhole (120mm) is exhaust, plus PSU is exhaust.
Making up a bracket for my Smartfan2 (80mm) so it blows directly on the ram and mosfet.
Got a bunch of microcool sinks to put on all the mosfets and voltage regs.

I know nothing is "safe" or "gauranteed" with oc'ing... but from experience, would you say my setup should be adequate for 3.2vdimm / 1.6vbt?
________
cheap vaporizers

Quote:

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Originally posted by uwackme
Once done, and set, the Vtt will track Vdimm... but the whole "window" of setting moved from stock bios range...2.6V-2.9V to a new range... 3.0V-3.3V (as set in my case) because of the Vdimm mod.

Within this new range, they track correctly. if I alter the Vdimm pot... I must then also alter Vtt pot, but once set, they track within the new range of bios adjustment.

The circuit the pot is in is a low current feedback loop, no risk of burning the pot up. Set for 3.0-3.3 range, my pot value was 90ohms.

It seems an incovenience, but once you dial in the new range, you wont have to bother touching the pots again....so it isnt really.

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This is very useful information.

Thanks.

The automatic vtt mod didnt seem to work for me...

I have used vdimm mod where I removed resistor and connected the closest to ram solder point to the farthest leg on the mosfet though VR.

I've set it up to that the bios to 2.9 and checked with voltmeter...it showed 3.31v on vdimm and then checked vtt voltage ont he double mosfet, 2 left pins showed it as 3.41 but 2 right ones showed them as 1.45

Is there anything i could've done wrong that would cause it?


BTW, about 2 mins later i went to check voltages again and shorted 2nd and 3rd leg of the mosfet... and pooof... gonna RMA the board tomorrow :\ so now i have some time to try to figure out what went wrong...


Thanks

Better hope your ram is still ok. Sounds like you messed up and had 3.XV on the Vtt/Vref line ..... badness. Vtt/Vref not to exceed 1/2 Vdimm period.

Key to no shorts...SHARPEN your multimeter probes...literally, use a file. Also, scotch tape, or coat in silicon glue all but the tippity tip. I use Huntron Tracker probes...cost me $15 at the time, been with me for 18 yrs now....needle sharp, insulated except the very tip.

Also, I have a Weller EC2001 soldering station spare I'll let go for $100 to someone in the USA.... costs $300ish new.

Friend just tested my ram for me, its fine.. phew...

The board is also already on the way to ABIT...

Next time ill be ALOT more careful :)

Guys, one question, why my Vdimm mosfet is DAMN cold????
I'm feeding them 3.2v's.... and its on room temp! :)
Tought it was the fan which i've blowing air on the Dimm's but even if i stop it, it still doesn't get even warm.
The only thing which gets warm is the Vtt tiny chip, and the thing is that i can't fit properly a small heatsink i've got with thermal tape...seems i've to add some artic epoxy or something to be perfectly in contact.

Cheers,
Byron

I thing this mod didn't help me much for higher FSB, I need VDD more than 1.85V to run perfect prime at 240 Mhz....

Please can you show me the effect of this VTT/VBT mod ?

I have fail at Vbt=Vdd mod (burn your Vtt chip) and VBT=Vref mod (make Your board goes down time by time), but maybe anyone here got a great thing to share about the "cut-trace" method...

or can you find some other way for it ?

More indepth testing..... and weird things appear.

On D10, with 2x 256M CH5 HyperX3500, multi 10x or 10.5x.

The rams pass memtests and ALL...ALL 2D testing at 11,2,2,cas2 @ 3.3Vdimm 1.65Vtt 1.85Vdd 1.875Vcore (2.520 Ghz)

BUT... heres the weird part. 3D testing fails. Isolated finally to the ram timing setting... xx, x, 3, x running top-to-bottom as listed in D10 bios. At 11,2,3,2.0 everything is fine, but 11,2,2,2.0 3D stuff crashes.

So the xx,x,3,x setting is touching on a northbridge/AGP issue. if I use a PCI 3D card, 11,2,2,2 runs fine.

No setting related to the AGP bus made any difference in making xx,x,3,x work at xx,x,2,x. I tried every combo of Vagp, 4x/8x, fastwrite/not sideband/not, AGP frequency, AGP latency that I could think of.

So the traditional 11,(3),x,x need of CH5 was gone at high Vdimm but what I hadn't bothered to notice previously was the AGP related need for 11,x,(3),x setting for happyness.

From the way I see it, both NVidia and the OEMs have done a piss poor job of configuring the memory controller.... and more so, letting skilled endusers get access to all the settings we need to make the most of the product.

Still no BH5 for me to test, I'll be interested in seeing if thier is any difference with everything else the same, vs CH5 in this matter.

So far, longterm, the cut-trace/pot version of the Vtt mod is fine, the mosfet isnt burning out, the Vdd-boost mod is fine, as are the motherboardFAQ's version of Vdimm and Vdd. 5 NF7-S's done up, all reporting no problems.

I did the 3 in 1 mod
So far no problems. I made the vdimm = v i/o detachable.
The best I could do with these mods is 242Mhz FSB.

Screenies:
http://kaine.studentenweb.org/pifast52.45.jpg
http://kaine.studentenweb.org/nf7-1.jpg
http://kaine.studentenweb.org/nf7-2.jpg

More info:

So I completed testing at 240Mhz x10.5. I turned all the goodies back on, 80Mhz agp (40Mhz PCI), 8x, fastwrites, agp apeture at 256M, etc. Ram settings at 11,2,3,2.0 cpuint enb. 9800pro at 450/410.

Totally 3D stable at this point, works like a charm, IE: fastwrites on/off, AGP freq 66-80Mhz, AGP apeture 64-256M all have NO bearing on stability. So I've hit my highest so far's.....

3Dmark2K1... 20796

3D03.... 6810

SiSoft mem: 3702/3463 cpu: 9631/3981

My hypothesis is the following.... the CPU to DDR interface in the northbridge is perfectly happy with 11,2,2,2 but the AGP to DDR interface needs 11,2,3,2 to be happy. The bios settings dont allow seperate entries for the two access modes. So we have to settle for the lowest common "happy" point.

So 3D instability can easily be NEITHER the CPU nor the RAMs fault, even though you might be led to "think" it was related. Something to keep in mind in all our future OC'ing efforts.

Proof positive will come from testing with a PCI based ATI9200 card, so NO agp access occurs at all.... I dont think there is a NVidia video PCI card that does all the DX9 tests.... GF2's dont.

Hence why you can have MEMTEST give perfectly stable results, no errors, etc, and yet you are NOT 3D stable..... now this makes sense. I dont know what about RAS-precharge causes this, but it's a datapoint for us.

EDIT: hmmm, spoke too soon? Dunno, went and tested FARCRY and it crashes at 11,2,3,2 but runs fine at 11,3,3,2.5.

Now at 250Mhz x10, 11,2,3,2 and everything passes for benchmarks, Ill have to set D3D back to no AA/AF and bench 3D again, but 3Dmarks pass with AA/AF on high ... 4x/8x... without crashing.

Hal, on the vdd booster that you did you soldered to a different point than what is on tictacs site, I guess it doesn't matter which point it is soldered to?

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Originally posted by rc7
Hal, on the vdd booster that you did you soldered to a different point than what is on tictacs site, I guess it doesn't matter which point it is soldered to?

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Ehm ... really? That's odd, everything is working though :)
Maybe I found out a new mod? :)