7900GT Voltmod-2

[Kin Hell]

Sorry to here of your woes Kin, I reckon its not just the Gainward but all the 512MB cards that use the non reference PCB, just my opinion

You may well be right alpha, it really is a GS card with the Bridge Chip still in place. I heard GW had to do this originally to get the card to work with with 512Mb. One way or another, I feel somewhat "Fudged" as both cards perform without issues as single cards. The Ram of these cards is really cr4p for OC'ing tho & the card become "unpredictably unstable". SLI 2 of these cards & they do the same!

[Kin Hell]

Edited Double Post

It's heat issues...that easy...1 card idles at 33, the other at 41. With the Hot card in the top slot (its the fastest of the 2), the heat from the bottom card just makes the top card too damned hot & thats why the the graphics are locking & BSOD's. This is happening at the Cards Default speeds btw!
To proove it, I swapped em round so the slower but Cooler card is in the top slot. This then allows the SLI'd cards to clock to 625/740, but the side panel has to be off. Put the side panel on, the cards heat has nowhere to go but upto the PWM & Northbridge Area pushing case Temps from 30 DegC on CPU, 40 on PWM & 43 on chipset to 45, 49 & 58...ffs! 2 x 256Mb BFG's never did this & those cards vented sideways through it's slim cooler. These GW's have a Bigger Cooler & Ram Sinks but it's blowing all the Heat from the cooler over the Power area of the card for cooling, which really is 4rse about face on Industry Standard case Air Flows. What are the graphics card manufacturers thinking eh!
My Rig is fine with one card & the side panel on, tho the hotter of the 2 cards on it's own will still start to throttle back after sustained gaming periods.
No wonder so many people are RMA-ing 4 cards to end up with the same issues & sustained use with these kind of conditions will just start blowing components on the cards. This is probably why my m8's GTX blew itself to bits. He had candy pink splodges, wierd textured artifacts & seriously reduced FPS numbers in 3DMark after his nuked itself.
You can't get much better Air flow as I have on my Lian Li PC75 Server Case, but I still can't believe the card manufacturers are cooling these cards 4rse about face to conventional case Air Flows, which really are an Industry Standard. Then again, it's a bit like Lian Li & their Upside down cases such as the V1000, 2000 etc. Quite an interesting design in some respects, and so nice to see your Graphics card & PCI devices the right way round, but then the Mobo manufacturers start putting Heat Pipes on the Chipsets & they DONT work upside down! You gotta laugh, it sure beats the hell outta crying but ffs at it all. The designers need their 4rses Spanking seriously hard!
Addendum: You can tell when the cards are going to throttle back when it's got too hot, you'll see the running Graphics Pause for a split second & then carry on. If you know what you're looking at, you see HUGE differences in the numbers....Like finishing Aquamark at 54 intead of 103 or seeing a best of 160 odd in 3DMark03's elevator when it should be 380+....Sheesh!

[kneif]

I made vmod with pencil on my Palit gf7900 gt 512 MB card, and now i would like to measure voltage of the core with multimeter. I read forums but i cant find explanation how to do that. Could someone paste a picture with marked points where i need to connect multimeter to measure volts ?

[Kin Hell]

Yeah the system boots, can hear the hard drives booting and the lights show it as well. Its like everything is working except not receiving the picture on the monitor. This gives me a chance to RMA my g.skill ddr500 2GB of ram though that never ran stable at DDR500. So im going to RMA the ram and the motherboard and hopefully ill be back to normal. I just hope ASUS doesnt take forever with RMAs but for some reason I remember some1 saying that they do. And like I said it was working fine until I plugged in some of the 24pin connector and it seemed like something got power that shouldnt have at that point because the PSU switch was on meaning althought it wasnt on it had power. After that, no picture. Teh psu boots the board up, hd's, optical drives and the graphics card has 1.55v on the core and the memory has power as well so its gotta be working. I checked the monitor cable, switched out the dvi/vga adaptor to no avail. Ive done everything I can think of, its going to suck taking everything apart though. The water cooling draining, the cpu block removal, gpu block removal, taking out everything, removing the mobo. Going to take quite a few hours. At least I can get my RAM replaced, I havent sent it away yet because I didnt want to be without my computer, its how I make money right now selling stuff on forums and ebay but I have no choice now. newegg is much better at RMA speed then asus so I should have the RAM back way before the motherboard. If its still not getting picture when the mobo gets back then will try to figure out which I should RMA first, the PSU or graphics card. I doubt the monitor is the problem, it says its working on the self test. It blinks for a second totally black when i turn on the PC then switches back to the blue/red/green box. Its like it got power for a second then stopped. Ahh, this blows. just hope the motherboard fixes it, the onboard audio doesnt work on the mobo either so thats getting fixed too.

Hows things looking for ya Smut?

Have you been able to draw any Conclusions yet?

I RMA'd the 2 x GW 512Mb Gt's and took an XFX XXX GX2....Core hits as high as 74 DegC, 86 with the Side Panel on! ....no lock ups tho & no BSOD's. I spect if Quad SLI ever becomes available to DIY Consumers, there will still be heat issues with the Lower SLI Card acting as a Blast furnace for the Upper SLI card! |Gunno have a look at increasing the Gap on the cards. I'll know more for splitting em!

Best of luck with your probs anyways!

[Kin Hell]

Yeah the system boots, can hear the hard drives booting and the lights show it as well. Its like everything is working except not receiving the picture on the monitor. This gives me a chance to RMA my g.skill ddr500 2GB of ram though that never ran stable at DDR500. So im going to RMA the ram and the motherboard and hopefully ill be back to normal. I just hope ASUS doesnt take forever with RMAs but for some reason I remember some1 saying that they do. And like I said it was working fine until I plugged in some of the 24pin connector and it seemed like something got power that shouldnt have at that point because the PSU switch was on meaning althought it wasnt on it had power. After that, no picture. Teh psu boots the board up, hd's, optical drives and the graphics card has 1.55v on the core and the memory has power as well so its gotta be working. I checked the monitor cable, switched out the dvi/vga adaptor to no avail. Ive done everything I can think of, its going to suck taking everything apart though. The water cooling draining, the cpu block removal, gpu block removal, taking out everything, removing the mobo. Going to take quite a few hours. At least I can get my RAM replaced, I havent sent it away yet because I didnt want to be without my computer, its how I make money right now selling stuff on forums and ebay but I have no choice now. newegg is much better at RMA speed then asus so I should have the RAM back way before the motherboard. If its still not getting picture when the mobo gets back then will try to figure out which I should RMA first, the PSU or graphics card. I doubt the monitor is the problem, it says its working on the self test. It blinks for a second totally black when i turn on the PC then switches back to the blue/red/green box. Its like it got power for a second then stopped. Ahh, this blows. just hope the motherboard fixes it, the onboard audio doesnt work on the mobo either so thats getting fixed too.

Hows things looking for ya Smut?

Have you been able to draw any Conclusions yet?

I RMA'd the 2 x GW 512Mb Gt's and took an XFX XXX GX2....Core hits as high as 74 DegC, 86 with the Side Panel on! ....no lock ups tho & no BSOD's.
I do have several 110 Event ID's saying the HW Clock has throttled due to Heat. I spect if Quad SLI ever becomes available to DIY Consumers, there will still be heat issues with the Lower SLI Card acting as a Blast furnace for the Upper SLI card!
Gunno have a look at increasing the Gap on the cards. I'll know more for splitting em!

Best of luck with your probs anyways!

[t024484]

After having looked again at the voltmod area, I found a third way to do your voltmodding.
This third alternative is the easiest of them all. You don't have to connect to ground anymore, and the mods can be done independently.
Red gives you +0.05Volt
Yellow gives you +0.1 Volt
Purple gives +0.2Volt
See picture below, on the lower row.

If you want just 1.4 Volt, make the purple connection, if you want 1.5 Volt use purple + yellow, etc.
If you have changed the 5 Kohm resistor into 50 Kohm, you start with 1.5 Volt instead of 1.2 volt, but the voltage steps remain the same with 0.05, 0.1 and 0.2 Volt.

[doom_st]

updated mod @ 1.7v max
1.6v 24/7 water gpu 720(+40 delta)
1.7v bench gpu 750(+40 delta)

p.s photo from se w900

[LiQU!D]

Heh, mine kept overheating and artifacting at 1.5V, probably because my system is with all silent fans.

[jmsandrsn]

After having looked again at the voltmod area, I found a third way to do your voltmodding.
This third alternative is the easiest of them all. You don't have to connect to ground anymore, and the mods can be done independently.
Red gives you +0.05Volt
Yellow gives you +0.1 Volt
Purple gives +0.2Volt
See picture below, on the lower row.
If you want just 1.4 Volt, make the purple connection, if you want 1.5 Volt use purple + yellow, etc.
If you have changed the 5 Kohm resistor into 50 Kohm, you start with 1.5 Volt instead of 1.2 volt, but the voltage steps remain the same with 0.05, 0.1 and 0.2 Volt.

Sorry if this is remedial but if I want 1.4v can I chose to connect whatever set of purple pins that I want to or do I need to connect all three purple sets.

[t024484]

Sorry if this is remedial but if I want 1.4v can I chose to connect whatever set of purple pins that I want to or do I need to connect all three purple sets.

The answer to both questions is a clear NO.
Read again, and you will find your answers.
Only this new third option gives you 1.4Volt by connecting the purple pins.

[xit]

The answer to both questions is a clear NO.
Read again, and you will find your answers.
Only this new third option gives you 1.4Volt by connecting the purple pins.

Is there a way to get 1.45v, or is it only 1.4, 1.5 or 1.55 ?

Thank you again t024484 for your wisdom.

[andre X_X]

Is there a way to get 1.45v, or is it only 1.4, 1.5 or 1.55 ?

Red gives you +0.05Volt
Yellow gives you +0.1 Volt
Purple gives +0.2Volt

you can combine (the color) this mod, so you can have 0.05v increments...

[t024484]

you can combine (the color) this mod, so you can have 0.05v increments...

That´s it

red 1.25
yellow 1.30
red + yellow 1.35
Purple 1.40
purple + red 1.45
purple + yellow 1.50
purple + red + yellow 1.55

[andre X_X]

its the easiest mod ever.... doesnt void the warranty, an as easy as drawing a line... thx to t024484

[CompGeek]

I have a question. If I were to solder that 50k ohm resistor for a 1.5v base, would it be possible to reverse the process sufficiently if I needed an RMA? I'm not afraid i'd fry my core, Im @ like 39C on load, im not sure my memory wasnt defective, and if it should eventually give out noticably I'd want a new card.

Currently @ 760/975 3d06 stable @ 1.54v/2.17v, 770/1030+ in AM3 (meaning, was atable here, havent gone higher)

[t024484]

I have a question. If I were to solder that 50k ohm resistor for a 1.5v base, would it be possible to reverse the process sufficiently if I needed an RMA? I'm not afraid i'd fry my core, Im @ like 39C on load, im not sure my memory wasnt defective, and if it should eventually give out noticably I'd want a new card.

Currently @ 760/975 3d06 stable @ 1.54v/2.17v, 770/1030+ in AM3 (meaning, was atable here, havent gone higher)

If you solder a 50Kohm resistor to replace the existing 5Kohm resistor, there is no way back for an RMA.
Keep your Voltage Regulator Mosfet cooled with a heatsink, and your memory will last forever.
And as as a last advice: do not use Coolbits. The best thing to do ist to set the 3D frequencies in your BIOS with Nibitor.

[CompGeek]

Owe this all to Quijonsith @ EOC

[t024484]

Owe this all to Quijonsith @ EOC

Why don't you use a SMD resistor like the one you took off. It is so much more stable, and less vulnerable.

[CompGeek]

because i didnt find any at radioshack

[andre X_X]

you can find it at farnell.com
anyway, if u decide to do the 50kohm mod, i suggest you to do this mod also. its a gread mod....

[andre X_X]

The best thing to do ist to set the 3D frequencies in your BIOS with Nibitor.

good advice, but the problem is we dont need the speed for daily using.... its only for bench..

[adamryer]

im getting 2 xfx 7900gts in a few weeks (the black ones to match my case), i plan on ocing it on stock volts, then jumping to 1.4, and eventually 1.5v they will both be watercooled. I was wondering if anyone could post a pic showing witch mosfet chips need to be heatsinked so they dont overheat? thanks.

[Z33ky]

Sweet guide t024484!

Regarding "resistor K", I measured it at 85-86kohm. Did the pencil-mod (bare leads 0,5 HB) and hit 44,6kohm. So the lower the resistance, the higher the switching frequency?

85k+100kohm = 45,9kohm.

Will high switching frequency have any negative impact?

Where exactly does one perform this mod? Is there a photo posted somewhere someone can refer me to which shows this pencil mod? In the photo t024484 posted (see below) which shows the place circled in lite blue for a 47Kohm resistor mod; is this the same place to do that pencil mod? Thanks in advance expecially to t024484 for all the work he's put into this!

[Alexstarfire]

Well, after looking through this thread, though not reading all the posts, I noticed that the v-mod using the chip is missing. The chip I'm referring to is the one in this picture.

I know for a fact it used to work on my previous eVGA card, but that was when the 7900 GTs had just come out. Now that I have a new eVGA 7900GT that mod no longer seems to work. I used a pencil both times so don't tell me to use a conductive pen. I'm just wondering if they did something to where this mod no longer works, or if it's changed in some way.

Thanks

EDIT: nvm, the mod does work. For some reason the stupid pins weren't connected even with a crap load of graphite on it. Anyways, I got it working. And here is a picture of the pencil mod:

[Z33ky]

@Alexstarfire,

The pins aren't stupid! It's best to use conductive ink or paint (silver based is probably the best) when soldering is to difficult...

Now will someone please respond to my previous post? Thanks!