System is similar to mine.
I can run it all very high with x2 AA and x8 1680x1050 AF at really decent frame rates, 24-45. one way i find to enjoy the game, and it applies to others. Its to just turn fraps off, and enjoy the game. Crysis has something that it does not feel that choppy when it dips below 30fps. I use very high overclocks when playing crysis specifically 840/2000+ and 3.6 on the cpu.
At 1080p you can probably max it with no AA, using Dx9 very high tweak,