GTX 680 Volt Mod

so.. been reading up.

I had a 3-way GTX 680, but one card was under volt. and my RMA failed cause this is Japan. (happens often here.)

In despair, I learned Volt mod, in hopes to fix my bad card.
and I think I found something.

there are 3 5ohm resistors that tells your GPU how much voltage is passing, and if I short them out, the read remains, but actual voltage is much higher, resulting is higher GPU base clock possible.

mind you, this card is on waterblock.. so temps probably not for those on air.
but as of now, I can get baseclock +450Mhz on first try.. and surprisely.. no crash. temp at 58'C on load on water. (and my card is an OC version, so base clock was at 1150)

my conclusion so far:
- It is probably possible, that nVidia purposedly underclock their Kepler chips for further upgrades and new cards. the Kepler chip to me, is CLEARLY capable of MUCH higher clocks. Though this is just day1, I am uncertain if the lifespan will be much shorter. ... nonetheless, thought I post my results.

3Dmark11 score, single card there was 13272.. (at clock 1600)

Update two:

instead of just shorting them out,
I now added a 1 ohm Resistor in parallel for all those 3 resistors I found.

result is a very stable clock.
Previously, I wasn't able to make it through Heaven Benchmark without the VRM throttling due to over voltage, now there's no problem.

anyone care for some pics? I can take some.
base clock now 1600Mhz. and manual calculations puts my voltage at 1.33V through the GPU. Temps are fine too. max 58'C on water still.

I will now put it on a 12 hr stress run, I will call it stable if it passes without failure. and I have a good feeling about this.

Stress test done. Didn't crash, temp went to 61'C max on water.

I will conclude that this is a doable fix to boost Voltage on the card
it is stable, can bench.

now... my problem is..

do I want to volt mod my other 2 good cards to match this?
.... dunno.

The theory about factory undevolting is actually very interesting...

Just a theory....
but does explain a little about why all the voltages are locked currently..

luckily.. easy problem to fix.

There is already information out about GTX680 volt mods on the Front Page. I believe explaining what you have found.

I think those are 0.5 ohm rather than 5 ohm, but yeah. That's part of the new push towards efficiency and low power consumption I think.
Those serve to tell the controller how many amps it is putting out so it can move voltage and clocks around to keep the card under TDP.

EarthDog said:

There is already information out about GTX680 volt mods on the Front Page. I believe explaining what you have found.

Click to expand...

didn't know it was covered!
and sure did a better job that I did !

but there we have it.

Do you have any pictures of what you did? I love seeing homegrown stuff as opposed to copied stuff. Plus, sometimes the homegrown mods pick up things that the "professional" mods miss.

Yes...yes.. pix please. Link was a supplement!

yeah, I can take some pictures tonight.
I think I did decent.

My question STILL being.. do I want to do this for my other two good cards.

I guess I will test this mod card in a test rig for 2 months before I decide, haha. Too many uncertainties about the card's lifespan afterwards. But I have a good feeling with what I did.. and the stablity seems good so far.

In theory if the temps are fine and the voltage controller isn't going nuts, it should last quite happily.
You might want to add a hard wired voltage read point, just for giggles.

Bobnova said:

In theory if the temps are fine and the voltage controller isn't going nuts, it should last quite happily.
You might want to add a hard wired voltage read point, just for giggles.

Click to expand...

that actually makes sense too, my only worry is over voltage from the parallel 2-5 mOhm resistor. a physical measurement can ensure that doesnt happen. I was thinking about adding a fuse to burn out if it over volts too, but just haven't found the right size for that yet.

Lol @ volt mod like that and you are worrying about the lifespan of the card.

Make that bad boy bleed yo! Don't go halfway!

hahah, you probably right.
the second I brought out my soldering pen out, I have already pushed it too far.

but it was a bit too easy when I saw the panel... couldn't... resist...