there's a few minor differences in the image quality in nvidia vs ATi, not sure how accurate they are, since I only get half the story and I don't play any of these games. There's a picture floating around of an image from stalker which has terrible quality on nvidia, and looks a lot better on ati. Then there's the new fiasco with catalyst AI and AF optimizations that make AF slightly worse for an 8% performance increase. Then there's the concentric circles which look terrible on nvidia, and awesome on ATi, though somehow nvidia's AF still works better.