imo, what I think the performance should be is enough that you can play at your max resolution with some detail. Honestly my 6600gt can play quite a few fairly new games on my 24" widescreen, even the 8800gts g92 generally is enough to give you at least 30 fps for my needs. Honestly, 300 fps looks and feels no different than 61 (as the eye can't detect the difference above 60 anyways), so what matters most to me is minimum framerate (which has shown to be a problem for 3870x2 and even occasionally the 9800gx2). If either the 4870 or 9900gtx (not gtx 280) can do that for me, then I have no need for anything better