ive gotten a score as high as 6520 in 3dmark05 i dont think ive ever seen 6800t or ultra come anything close to that. but at stable speed i still score 6400
a friend of mine just sold his x800xl so i know how they perform, there not to great at overclocking, even with a zalman vf700cu on there.. the cards core could only push about 430mhz from 400mhz. and the memory reached about 1080mhz from 980mhz, but it was solid stable with drivers, and he got about 5600 in 3dmark05 which to achieve that with a 6800gt you would have to do some crazy overclocking.. and people dont call me some ati fanbody i just go buy what performs for the money. becasue ati has a video card for every kind of gaming u want to do. nvidia its either 6600gt which is decent or 6800gt a little better or pciexpress which im mean the 7800gtx. and thats no selection it all