i'm not running any AA(can't figure out how to enable it through nvidia's terrible new control panel), all settings in LFS maxed out except for the paying for high res textures, and in a racing in a pack. i'm pretty sure those resolutions you posted are what i turned mine down to last night, softth handles the "extra" 26 pixels fine. and from what i've read, ALL of the rendering is done on your main card, and the second card is just getting the data passed through it so it doesn't need to be that fast, it just has to be PCI-E so it has a fast bus speed. i would say that a 6200/7100 would handle that fine.