I'm running this game on 2x HD 5770's and after hours of tweaking and trying to look for support (btw, I have CCC 11.4 preview and the new profiles) there's horrendous flickering and even more massive drops of FPS. The only fix I've managed so far is to rename Crysis2.exe to Bioshock.exe - quite a ridiculous fix that should not even be needed.
This game wasn't ready to be released and it's still not ready to be played 2 weeks after coming out.
With the Bioshock fix I get a maximum of 60 FPS, usually averaging around 45. After half an hour of gameplay they fall down to 30 FPS and below so there must be some sort of memory leak. I have 8 GB of RAM.
The multiplayer is sub-standard. Very slow paced although not as bad as some other games. There's been quite a few times I have spawned literally infront of someone and gotten killed straight away.
There's so many bugs for example my load outs not saving, steady aim (or point fire enhance, whatever you call it) is buggy. You have to fire a few shots in order for the crosshairs to become small as intended to.
The close range combat in this game is also ridiculous, there's so many times a guy is infront of me and I don't ADS yet almost every bullet misses them, it's an absolute joke.
This is not the product I spent money on buying. Get your act sorted and get this game fixed.