The Simple & Concise 7900GT Voltmod Tutorial

[1Dark1Sharigan1]

Quake 4:

@700/1800

1280x1024

Min: 36
Max: 218
Avg: 109.266

1600x1200

Min: 25
Max: 174
Avg: 88.114

@500/1500

1280x1024

Min: 27
Max: 179
Avg: 88.442

1600x1200

Min: 19
Max: 151
Avg: 67.944

@450/1320

1280x1024

Min: 23
Max: 167
Avg: 79.247

1600x1200

Min: 16
Max: 142
Avg: 60.561

 

[iamtrout]

Originally posted by: fuzzybabybunny

Originally posted by: keysplayr2003
OP: I have copied all of this info from the first post. If you wish, I can turn it into a nice web page with photos and host it. This sticky won't last forever, but the web page could stay as long as you like.

Keys

EDIT: Done. Here is the site.
If you want any changes, PM me. Thanks again for the great guide. I know I'll be using it. :beer:

OMG thanks yay! It looks perfect

<3 keysplayr2003

Link in OP?

 

[fuzzybabybunny]

Just updated with keysplayr2003's webified version

 

[nib95]

Originally posted by: fuzzybabybunny
Just updated with keysplayr2003's webified version

His webified one isnt workking
Not like yours didnt do the trick though, so no worries.

 

[1Dark1Sharigan1]

You guys using heatsinks on the RAM, do they tend to stick well or do they tend to fall off occasionally?

 

[imported_killerbobjr]

I came across this post here which mentioned cleaning the areas around the pencil vmods. Well, I thought, what the heck let's give it a shot. Sure enough, my 7900GT stopped blanking on me. However, my memory overclocks were still limited to around 800 vs. the 880 I had gotten when I first overclocked the card.

I looked at the back of the board against the light and noticed that there was all sorts of residue left over from the assembly/soldering. Most of the time, the assembly factories do a quick wash to get rid of all the flux material on the circuit boards. This is usually good enough. However, when we start doing our mods, we're not always too careful and lay our sweaty, oily hands right across the components. This adds conductive paths across circuits and causes instabilities.

Here's what I did and what I recommend:

1. Get a bottle of 90% Isopropyl alcohol. Pure acetone (nail polish remover) should also work.
2. Get a roll of paper towels.
3. Take one paper towel, saturate a corner of it with alcohol.
4. Scrub vigorously the areas around the chips that control the memory and gpu voltages. Also scrub the components opposite each the ram chips. As your paper towels shreds, soak a fresh corner and continue. IMPORTANT: Don?t put your hands or fingers on the freshly scrubbed areas!
5. Get a clean paper towel and rub vigorously, sopping up all the alcohol. DO NOT BLOW ON IT TO DRY!
6. Hold up the board at an angle and look for any traces of residue. Use a magnifying glass if necessary. Repeat steps 4 and 5 if any residue is detectable. The board should look absolutely shiny.
7. Do your volt mods. DO NOT blow on the board to dry or to blow away graphite from a pencil mod. This will leave residue from the moisture on your breath. Use a can of compressed air instead (if you use an air compressor, make sure it has fresh oil and moisture filters).
8. Put your video card back into your system holding it only by the edges and bracket.

After you do this, your results hopefully will be similar to mine ?

7900GT before cleaning:
GPU = 630MHz @ 1.4V and high fan speed (VF900), no artifacts, no blanking
Memory = 800MHz @ stock volts, no artifacts, no blanking
-- with pencil volt mod, 840MHz, no artifacts, but lots of blanking.

7900GT after cleaning:
GPU = 650MHz @ 1.4V and LOW fan speed (VF900), no artifacts, no blanking
Memory = 940MHz @ STOCK volts, no artifacts, no blanking!!

My 7900GT is now rock solid stable even at the low fan speeds.

- kbj

 

[Sunrise089]

Great tip/guide killerbobjr

 

[Keysplayr]

Originally posted by: nib95

Originally posted by: fuzzybabybunny
Just updated with keysplayr2003's webified version

His webified one isnt workking
Not like yours didnt do the trick though, so no worries.

Anyone else have any trouble getting to the web version? It seems to be working fine.

 

[Sunrise089]

no problem here

 

[inveterate]

YO guys in this post http://www.xtremesystems.org/forums/showthread.php?t=94177

IS THIS UBER IMPORTANT , like is everyone getting the blank screens,, because this talks about a pencil mod for something with switching frequency + energy packets.


To make a long story short, it was not the overvoltage protection giving me problems, neither was it the overcurrent protection. It turned out to be that with the preset switching frequency, the convertor could not supply enough energy.
This type of "bucket"convertor supplies a packet of energy with each bucket that is tranferred at a clock period. To get more energy, more buckets have to be transferred, and hence the swiching frequency has to go up.


http://www.xtremesystems.org/forums/att...nt.php?attachmentid=45296&d=1143538288

And than comes a very important Mod, being resistor K.
This resistor measures ca 80Kohm, and sets the switching frequency.
Connecting a 100Kohm resistor in parallel, almost doubles the switching frequency, and solved my problems completely.
You could eventually do this mod by pencil, try to get the value down to approx. 45Kohm.

 

[1Dark1Sharigan1]

So finally installed BF2. Also have Lost Coast benchies.

BF2:

@ 450/1320

1280x1024

Min: 66
Max: 100
Avg: 80

1600x1200

Min: 48
Max: 74
Avg: 60

@ 500/1500

1280x1024

Min: 75
Max: 113
Avg: 89

1600x1200

Min: 54
Max: 83
Avg: 67

@ 700/1800

1280x1024

Min: 84
Max: 143
Avg: 106

1600x1200

Min: 71
Max: 108
Avg: 87

HL2: Lost Coast VST:

@ 450/1320

1280x1024

Min: 35
Max: 174
Avg: 73

1600x1200

Min: 29
Max: 132
Avg: 56

@ 500/1500

1280x1024

Min: 38
Max: 183
Avg: 81

1600x1200

Min: 32
Max: 132
Avg: 62

@ 700/1800

1280x1024

Min: 43
Max: 206
Avg: 100

1600x1200

Min: 40
Max: 177
Avg: 80

 

[cronic]

nice consolidation of info, but you should give a little credit to the guys at Xtremesystems.org who did all the hard work to figure out this mod in the first place.

 

[imported_killerbobjr]

YO guys in this post http://www.xtremesystems.org/forums/showthread.php?t=94177

IS THIS UBER IMPORTANT , like is everyone getting the blank screens,, because this talks about a pencil mod for something with switching frequency + energy packets.

I actually tried that before coming up with my approach for cleaning the board above. Used a pencil and tried 45K - got blanking, cleaned the graphite off, tried 60K - got blanking, cleaned the graphite off, tried 80K - got blanking, tried 30K(!) - got blanking. Trying this mod actually made the problem worse -- my maximum GPU and memory frequencies went down, down down.

When I thoroughly cleaned the board as I described above, ALL my blanking problems went away completely!

When you think about it, it makes more sense to make sure everything is within the original design parameters rather than trying to change the V+ charge frequency. That circuit was designed for a specific set of charge times. Upping the switching frequency will throw the entire duty cycle off and probably cause instabilities elsewhere. If, instead, you clean the circuit board so that: A. Your switching cycle is now within the design parameters; and B. (most importantly) your switching waveform is now as close to square as possible so as to maximize the charge times, you will get enough energy in your V+ circuit to easily supply the GPU and memory without needing to do things like remove overprotection circuits or change switching frequencies. Cleaning the board removes any conductive paths and stray capacitive loads that will degrade the V+ switching waveform.

If any of you are not convinced by this, let me ask you this: What have you got to lose? If you clean the board in the manner I describe above, at the very least you will have a solid foundation to try the other mods on.


- kbj

 

[Dexmaus]

killerbobjr, i followed your guide, cleaned the back board, redid the vmod, right now im stable at 675/1840

used to be 625/1600 (blanking crazy sometimes)

thanks, if you guys got problem with blanking make sure clean the back board with some acetone, my back board was all sticky before i clean them, i guess that was causing the problems with artifact and unable to raise my memory clock higher than 1600.

 

[fuzzybabybunny]

Originally posted by: killerbobjr

Thanks! Updated!

 

[Keysplayr]

Originally posted by: fuzzybabybunny

Originally posted by: killerbobjr

Thanks! Updated!

Updated site as well. Also consolodated all of 1Dark1Sharigan1's benches.

 

[nib95]

I just took the plunge on a Silverstone ST75ZF (the new 750w badboy) along with two Zalman VF900's.
I already have the AS5, Conductive pen and so on, so I will be voltmodding both my 7900 GT's very soon indeed!
Hopefully tomorrow as that is the estimated delivery time! W00t!!!

 

[nib95]

When you guys say 'use' alchohol.
Do you mean the chemical, or just the drink.
As in, could I just buy a bottle of spirits, say Vodka or something and would that do the trick?

 

[1Dark1Sharigan1]

Originally posted by: nib95
When you guys say 'use' alchohol.
Do you mean the chemical, or just the drink.
As in, could I just buy a bottle of spirits, say Vodka or something and would that do the trick?

lol no. You'll want isopropyl alcohol, (rubbing alcohol) 90% or better.

You can also use acetone or nail polish remover.

 

[nib95]

Originally posted by: 1Dark1Sharigan1

Originally posted by: nib95
When you guys say 'use' alchohol.
Do you mean the chemical, or just the drink.
As in, could I just buy a bottle of spirits, say Vodka or something and would that do the trick?

lol no. You'll want isopropyl alcohol, (rubbing alcohol) 90% or better.

You can also use acetone or nail polish remover.

Ok many thanks lol, was going to say, was a bit unsure.
Because I know alchohol (the drink) also has cleaning properties.
But I suppose thats namely in the realm of being used as an anti-ceptic.

 

[inveterate]

Originally posted by: nib95

Originally posted by: 1Dark1Sharigan1

Originally posted by: nib95
When you guys say 'use' alchohol.
Do you mean the chemical, or just the drink.
As in, could I just buy a bottle of spirits, say Vodka or something and would that do the trick?

lol no. You'll want isopropyl alcohol, (rubbing alcohol) 90% or better.

You can also use acetone or nail polish remover.

Ok many thanks lol, was going to say, was a bit unsure.
Because I know alchohol (the drink) also has cleaning properties.
But I suppose thats namely in the realm of being used as an anti-ceptic.

HAHAHA you were about to pour sticky suger onto ur card. LOLOLOL

 

[inveterate]

Yo guys umm,, What did you mean YOUR board was STICKY before you cleaned it.. like it came sticky? or did you make it sticky..?? And by clean you mean the ENTIRE back of the board,, or just certain areas around the place you do the pencil mod

 

[crazylegs]

Originally posted by: nib95
I just took the plunge on a Silverstone ST75ZF (the new 750w badboy) along with two Zalman VF900's.
I already have the AS5, Conductive pen and so on, so I will be voltmodding both my 7900 GT's very soon indeed!
Hopefully tomorrow as that is the estimated delivery time! W00t!!!

Sounds like your going to have a nice rig there!

Hope that the vf900 fit in SLi on your mboard though... because i dont think they do on all of them...!

GL dude

 

[nib95]

Originally posted by: crazylegs

Originally posted by: nib95
I just took the plunge on a Silverstone ST75ZF (the new 750w badboy) along with two Zalman VF900's.
I already have the AS5, Conductive pen and so on, so I will be voltmodding both my 7900 GT's very soon indeed!
Hopefully tomorrow as that is the estimated delivery time! W00t!!!

Sounds like your going to have a nice rig there!

Hope that the vf900 fit in SLi on your mboard though... because i dont think they do on all of them...!

GL dude

Yea it will, because the Lanparty Nforce4 eXpert has quite a large space between the SLI slots, enough for two 7900 GTX's infact.

 

[Dexmaus]

Originally posted by: inveterate
Yo guys umm,, What did you mean YOUR board was STICKY before you cleaned it.. like it came sticky? or did you make it sticky..?? And by clean you mean the ENTIRE back of the board,, or just certain areas around the place you do the pencil mod

I guess the back of my card came sticky, i just found out that yesterday before cleaning it, its only one side tho, but i decided to clean the whole back board with some acetone and toilet papers, well, right now i've been playing Oblivion for 1 hour, the max temp is 56 with VF900. i'm running at 675/1840 very stable, haven't seen any artifact at all.
not planning anymore overclock, this speed is very good for me right now. thanks everyone here for the help~! great posts

for those people that using the conductive pen from Radioshack, it will be so hard to do it with the pen cause the pointer is too thick, i did this with a sharp pin, i squeeze some silver ink out from the conductive pen on a peice of paper and dip the pin then draw it on the board, it takes some patient, i've re-done it for a couple of times before making it neat.