GTS>GT. Period. DDR2 is slower than DDR3 so that is actually a BAD thing about the GT you listed. Neither card is fast enough to leverage 1024MB of texture memory... If it was really a good thing then why don't all the high end cards use 1024MB? 512MB would probably be a waste on both cards although might help a bit on a GTS. How much were you planning on paying for either card because the HD3850 is a lot faster than a 8600GTS and shouldn't cost too much more?