6950 Won't OC

[Wiz Khalifa]

My 6950 won't overclock. I can overclock it about 20MHz over it's factory overclocked state (850Mhz and 1300MHz). The main issue is that I never see artifacts. My driver just crashes. My screen turns black when in game then crashes to the desktop saying the "atimdag" or something crashed.

 

I decided to test my RAM first to see if there was a problem. I took out one stick and used the other one. BTW my RAM is Kingston HyperX 8GB RAM 2X4GB 1600MHz.

 

I was able to overclock my system to about 925MHz on the core and 1325MHz on the memory (because it is locked in MSI Afterburner). I am able to play it but it crashes after about 30 min of playing a game. I place the other stick back in and take the other one out. Same thing happens. I am able to overclock it but it crashes 30 min into the game. I don't see any artifacts on the screen while I am playing.but it just crashes.

 

I tested the RAM for 2 days on each stick and there was no errors what so ever.

 

All of my specs are below. Please help me decipher my problem. Thanks

[kaneandtaker]

Increase Vcore. Games crashing without artifacts means its an unstable overclock on the core. Nothing to do with RAM

[killerx525]

I've got 2 6950 and the stock clock was 810mhz, i've managed to get it at 880mhz and 1260mhz. Your card is probably at it's limit and it all depends on the silicon lottery but you could try bumping the voltage but beware, these cards can get hot even with a fairly beefy cooler like Asus's DCII.

[Wiz Khalifa]

Thanks guys, I will try it out and come back and tell you my results

[Wiz Khalifa]

This is getting really wierd now. I didn't overvolt it. All I did was increase the core to 900MHz. I get the screen flickering at some parts of the screen (I am using Windows 8). It only flickers when I open an application or enter the start menu or something. The screen does not flicker while I am in the burn-in test. It appears stable but it seems too hot (92 degrees). Even when I reset the clocks, the screen still flickers. I have to put the system to sleep when this happens, then when I wake, it is fine.