Just changed my card from fx5900(non xt) to 6800gt and ran aquamark 3 on old and new card and was amazed at difference.
on old card, I got a max fps of 38.32(at stock speed) and a total score of 38,321. On new card(at stock) I got a max fps of 58.27 and total score of 58,270.
btw, it gives triangles per sec as well(old card 11,536,150 and new card 17,541,316). Does triangles per sec make much diff?