Isn't most 2900xt 512 MB? So it should perform better than 8800gts 320 MB, yes?
What about 8800gts 640MB x2 vs 2900xt 512MB x2?
How much does the MB matter anyway? I assume it has to do with texture mostly?
Also if I remember right, SLI need to be a bit more careful when choosing motherboard; what about crossfire? Anything I need to be cautious about?