2 minute education:
Heat doesn't cause the artifacts. Heat damages your VRAM. VRAM gets corrupted. Game tries to write to faulty VRAM. Faulty VRAM spits back corrupted data. Artifacts!
2 minute math.
Transitive property.
If a = b and b = c then a = c.
If heat causes memory damage and memory damage causes artefacts, then heat causes artefacts.
If your card was damaged, you probably wouldn't know it right away, but it most likely is permanently damaged, no matter how cold you have it.
If GC2 is the only place he is getting artefacting, then it's more likely the cause is a corrupted file.
Don't tell me it's not your card. If it's not your card, then it's something else in your system. I'm pretty sure you're not the only one with an 8800GTX and the new drivers... (Wait, I have them too!)
Heh...ultimate arrogance. IT'S YOUR CARD, DON'T TELL ME OTHERWISE. Unless ...it's something else wrong. (Those seeem to be the only 2 options, thanks for your insight) If you were a doctor, you'd make diagnoses without running any tests.