i recommend you get a custom config for the graphics settings, since they can get you higher graphics settings than very high and improve your framerate. somewhere in that thread Pighardia linked to is the custom config TheCenturion gave me, and it works great for me (~40FPS @1360x768 with a lowly GTX460)
How would I get a custom config? I'm a complete noob when it comes to installing mods...
I can run crysis well (30-40 fps) at 1920x1080, everything on highest settings except post processing to get a better framerate.