I have exactly the same problem with the sme screenshots, its not just Crysis, its every high demanding game. First i thought it was my CPU wich temperatures were a bit high, 68C (intel q9550 quadcore). Placed a new CPU cooler on it and now he temperatures arent above 50C but the problem still remains.
My GFX (evga gtx285FTW) has been RMAed and there were no errors found at all. Nor the fabricant nor the dealer found any problems with several tests.
Read somewhere it could be my PSU, delivering false power or something like that. SO my next step is finding out if thats the case.