I have tested various combinations of both forced hardware and software settings (SSAA/AA/AF) and I get NO noticeable changes in performance whether I turn it all on or off (25-45 fps depending on what's being rendered). My rig is no super computer (i7 950 @ 4ghz, 12gb DDR3, HD5870), but I should in theory be having zero issues pushing a game of this caliber into or above a stable 50-60 fps.
Badly optimized is an understatement.