7900 GS / GT Volt Mod

[ziddey]

You can get ink from those circuitwriter pens, or from your auto parts store (some walmarts too). From auto stores / walmart, you'd be looking for rear window defrost repair kits. It comes with a little container of copper ink.

I'm not sure what a safe max would be. I know of many people running 1.55v, but I've also heard of a few cases of degradation as a result of it. I've been running 1.5v since January on a mcw60 waterblock, and my temps never exceed mid 40's under load. Haven't had a problem yet.

I'd probably personally stay with 1.5v as a max on good air. I know some higher end 7900's switched vid to 1.45v in 3d mode iirc (I know some switched to 1.3v only though), so I imagine that should be ok. Then again, they switch back down for 2d...

As for the ram, right, you shade both ends of the resistor. By doing so, it's like creating a parallel path, thus lowering resistance. A dmm would definitely be extremely wise. However, that said, the 7900's aren't really bandwidth starved, and it's really not worth the effort and risk in overvolting the ram. But if you do, make sure to cool the ic next to where you shade the resistor. It can get extremely hot and lead to instability / abnormalities.

[KoolDrew]

How should I cool the IC? From what I've read you can mount two fans on the V-1 Ultra, one on the back and one on the front. I don't know if it would cover the IC though. I just ordered the V-1 Ultra today. Also, when he says "anywhere from 2.0v to 2.6v" how is this determined?

[Vatos_locos]

everything ok with me i soledred the VR in pareler with the resistor for the mem and it's working great the Vr was a 10 K pot trimer
KoolDrew that's how i am cooling this card plus an 80mm fan on top of them

http://img167.imageshack.us/img167/1421/hpim1405ui2.jpg

[KoolDrew]

When I get the V-1 Ultra I will be able to get a better idea on how to properly cool it. I think I'll just start with 1.4v and then go up to 1.5v. If that works well maybe go to 1.55v, who knows. :P

[Cupcake]

Just to let you guys know , I will be soon selling my pair of Vmodded (1.5 Core 2.35 Mem) Cards with EK FC79 Blocks on them.

Just wanted to give you guys a heads up if you have any final questions before I get rid of these

PM me if you have some questions

[KoolDrew]

I guess the RAM chips on my card suck. Bumped voltage up to 2.18v (tested with a multimeter) and couldn't get even a single MHz faster than I could with stock volts. Could not having cooling on the IC's regulating the memory voltage have something to do with it, or do my chips just suck at overclocking?

My core increased from 564 to 685 with 1.507v though (again tested with a multimeter).

[ziddey]

what's your ram running at currently?

[KoolDrew]

what's your ram running at currently?

745. It was running at that before the volt mod as well. Got it up to 2.18v (tested with a multimeter) and try 746 and my PC just freezes and has lines going across the screen. Perfectly stable at 745 though. Even if my RAM just sucks at overclocking, I'd think I would at least get a little more with added voltage, but I guess not.

[NJDevilsFan21]

I tried this on my 7900GS and it worked perfectly. On my 7900GT however, it doesn't seem to work. Multimeter still reads 1.2V when using conductive ink on the 7900GT.

Does this not work on all cards?

[SaII]

I tried this on my 7900GS and it worked perfectly. On my 7900GT however, it doesn't seem to work. Multimeter still reads 1.2V when using conductive ink on the 7900GT.

Does this not work on all cards?

probably a bad contact

[Vatos_locos]

dose anyone know a point in this card to take 5Volts ? i wan to put a thermometer on her but it's 5 volts

[NJDevilsFan21]

probably a bad contact

Yeah you were right about that, got it worked.

Does anyone have insane memory on their 7900GS/GT? On my older XFX model, and newer BFGOC model, they use different memory (XFX uses some kind of Samsung memory, and I forget what the BFG used), but both are hitting 900MHz (1800MHz DDR) stable at the default 2.0V - and I'm actually wondering, has anyone ran speeds like this over an extended period of time and not had their memory fail? (I do use RAM sinks by the way)

[Vatos_locos]

i'am having 1010Mhz (2020Mhz DDR) rock stable on my evga 7900Gs with 2.2 Volt's more than a month now and the pc is on 24/7

[0Ro!]

I tried to vmod my EN7900GS, i used some info from t024484 in this thread http://www.xtremesystems.org/forums/...=7900+volt+mod ...so thanks for the info

with vGPU=1,789V, vMem=2,4V, OCP mod and modded the switching ferquency I could reach 815MHz for GPU and 1075 for the memory - benchmark stable
the card was cooled by Accelero S1 and 2x120mm Fans and some homemade heatsinks

here´s some fotos from my mod, not so clean as others but works fine





in our town it´s hard to buy VR, so I used normal rezistors

[bartx]

Very nice clocks - gratz. Any scores? Voltages are quite high - card may die one day

[0Ro!]

thanks man

here some crapy results

3D Mark 05


3D Mark 06


3D Mark 03


Aqua


need more voltages for the core...maybe 1,9V would be good

tommorow i will use my new homemade WB so i would see how the temperatures are...if i can use more voltage