Stability issues with volt modded 7900 GT

[freeflow]

Hi,

As the topic title says, I'm experiencing stability issues with my volt modded 7900 GT when overclocked. I think this post would be probably be easiest to follow if I summarised everything in point form, so here goes:

1) I'm running the following config:

Core 2 Duo E6600 @ 3.20 GHz (stock volts) with Thermaltake Beetle
Gigabyte GA-96P-DQ6
2 x 512 MB Corsair DDR2 667 @ 720 MHz (stock volts)
256 MB XFX 7900 GT Extreme Edition (volt modded to 1.5 volts) with Zalman Fatal1ty
Bog standard 500 watt PSU
nVidia Detonator drivers (91.47)

2) I volt modded the card to 1.5 volts using conductive ink.

3) I installed the latest version of ATITool, clocked the card up to 650 MHz on the core
from 520 MHz (fairly conservative for 1.5v), and ran the artifact test (without errors)for a couple of hours to make sure that it could handle it. Max temp was 66C, which seemed reasonable seeing as it was at least 28C in my room at the time. I decided rather not to touch the memory clocks for now.

4) I started up Company of Heroes and joined a friend's game. Everything seemed to be running fine, with absolutely no signs of artifacting or other graphical anomalies. After about five minutes of play, my LCD displayed a 'no signal' message, and a couple of seconds later my PC reset.

5) I decided to restore the card to stock clocks for the time being, and finished three games of Company of Heroes without any problems.

6) The next day, I did the volt mod over again just to make sure that I'd done it properly, ran the artifact test for a couple more hours - once again without any errors, and clocked the core back up to 650 MHz. I played Unreal Tournament 2004 for a few minutes, and my system reset again.

7) I tried the core at 645 MHz and 640 MHz just for interest, with exactly the same result.

My first hunch is that my power supply might be the problem, and that it's a voltage fluctuation when my card's under heavy load that's causing my system to reset.

Of course, I could just have a crappy core, but it'd have to be really crappy not to be able to hit 640 MHz at 1.5v, when most people seem to be able to hit 700 MHz at 1.5v.

Other than that, I don't know what the problem could be. 66C is well within the reasonable operating temperatures for this card, so heat can't be what's causing my PC to crash.

I see that there's a PCI-E voltage setting in my BIOS (GA-965-DQ6 motherboard) - is there any chance that increasing this to compensate for any voltage fluctuations would help, or would doing so just fry my card?

Any advice that you guys could offer would be much appreciated.

 

[Baked]

Any advice that you guys could offer would be much appreciated.

You fvcked up the card w/ the volt mod. Buy another one.

 

[Noubourne]

You say it's a conservative clock for 1.5v, but that's pretty much a nonsensical statement. Every core is different.

Did you test it at 1.5v at stock clocks? Stability testing the vid card should include the quick artifact test, and a run through of every game in your system and all 3 3dmark proggies. Basically everything you can throw at it. Once you've verified that it can take the 1.5v at stock clocks, then you start actually overclocking it. It could be that your conductive ink volt mod is unstable for some reason.

"Bog standard" doesn't have any actual meaning either. It COULD be your PSU. All brand new hardware and a no-name PSU? If you found a rusty old barrel of gasoline on your great-uncle's farm, would you tap it and immediately pour that gas into your brand new turbo-charged BMW 700 series car? No one can say for SURE that it's your PSU (you might be able to find fluctuations using a multi-meter though), but geez I wouldn't want to have to worry about it.

 

[customcoms]

And I wouldn't run a DFI Ultra-D off an Antec PSU unless its on dfi-street's list, though that NEO is a good psu that I'd use with any other board.

As for the OP, look into getting an OCZ GamerXtreme 600, they're on sale at monarch (if you trust them) right now. otherwise, check this list: http://www.dfi-street.com/forum/showthread.php?t=10854

It sounds like you are having a power issue, but your card could have problems. I would start with a new psu!

 

[freeflow]

Thanks for the reply.

You say it's a conservative clock for 1.5v, but that's pretty much a nonsensical statement. Every core is different.

I get what you're saying, but going by the average overclock that people seem to get out of these cards, 650 is a pretty conservative overclock. I'm not saying that it's 100% certain that my core should be able to handle this sort of speed, but it'd have to be pretty crappy for that to be the reason why I'm having problems at 640.

Did you test it at 1.5v at stock clocks?

Yeah, I've now tested it at 1.5v at stock clocks, and it runs everything perfectly.

"Bog standard" doesn't have any actual meaning either.

Hehe. When I put my system together, I couldn't get hold of the PSU that I wanted, and I had this one lying around, so I decided to give it a go. I would've swopped over to something else by now if I'd experienced any stability issues prior to this, but as I said, my rig was rock solid until now. And it still is, provided I run the GPU at stock clocks.

Thanks again for the reply.

 

[freeflow]

Thanks for the link, customcoms.

I guess it's about time I got hold of a decent PSU, regardless of whether or not doing so will help my overclock.