I'm running maxed out except SSAO is off at 2560 x 1600 and while the FPS dips into high to mid 20s on occasion even then the feel is still fluid enough for the game to remain perfectly playable. At 1920 x 1200 it's far smoother of course, just needs decent FSAA (forcing it via the NV CP does nothing, even with the latest full-screen patch, and the game's own x8 is lacking effect).