I have a phenom II x6 @ 3.78ghz with crossfire 6850s and I have difficultly running this game faster than 40 FPS on 1080p. Conversly I can run crysis on max at 60 fps and crysis 2 Dx11 at 60 fps on max (as well as many others) Regardless of settings, the only ones that really effect my performance are the view distance, AA and the environment detail (trees and stuff)