What exactly makes a graphics card crash?

I have a 3gb 555m gf116 graphics card that can only overclock to 700mhz without crashing. I really don't understand exactly how or why it crashes, I always thought crashes occurred when a temperature got to high, but mine only gets as high as 65c before crashing. At 730mhz it's completely fine for a while, no artifacts or anything...for example on 3Dmark06 I get through the first demo fine with no artifacts and stay below 65c but I get a black screen halfway through the second one and when I look at my clock speed it's back at 590mhz, the stock speed. I don't even get a "driver crash" notification from the nVidia control panel. So is it even crashing or just setting the clock speeds to default for some reason causing the application to crash? I just don't understand how why it crashes because no signs are shown that it's going to. You would think it would start showing artifacts and the temps would get like 80c+ but I get no artifacts and a stable temperature...but still a crash. Is this normal or is something weird going on with it? I'm kinda feeling funny about spending over $1,300 on this computer now, does anyone else get weird sudden crashes like this?

 

could be the voltage. I've had similar things with my old 460m. It artifacted at around 830mhz where most other people were rather stable, and I couldn't get the clock speed higher than that. Other people were getting up to 850mhz without issues. Same goes for all cards sadly, some can handle the heat/volts better than others, and yours just doesn't like the OC'ing.

 

ive been able to clock mine to 850 easy, but most games dont run stable on it

 

Not all GPU can be OC freely, the example is to what elmo93 having right now. My GT555M also capable of OC up to 870/1740 as well but only one game which is CoD 4, able to run it without crash, anything else would crash until I downclock to 800/1600 that all of the game I play perfectly stable, however BF3 used to crash at this point as well but after the last patch, that problem seem to fix.

If your GPU can run at default, then it mean there is nothing wrong with the card, because OC mean you force the GPU to run at a higher speed that the GPU suppose to run at, and dont forget, OC your GPU will cause its life time reduce depending on how high you OC as well. Unless the GPU crash at 590/1180 then Dell will not replace the GPU, however for the GF116 version of the GT555M seem to cause many problem such as hardware unrecognisable with the NVIDIA driver and some other performance issue with some games.

 

Well I know it couldn't even make it as far as it did without the voltmod bios. Is there anyway to make the voltmod more than .93 volts then? Also, I know my gf116 isn't compatible with any bios older than the newest one.. it's weird.