Ignore the guys talking about switching over to the Green Team. At this point AMD and NVIDIA are pretty much equal to eachother, AMD is better at some games and Nvidia is better at others. I just jumped ship from nvidia recently because i was having terrible problems with their drivers. I've never used an AMD card until recently and i have been running Nvidia cards since the days of 6800.

Run a driver Cleaning program ( i use driver sweeper myself) and install your new drivers then reinstall crysis. If that doesn't work then it may be an issue with your OS or it could be something on Cryteks end.

again switch to nvidia.