Quote Originally Posted by tajoh111 View Post
10-15% maybe to a gtx 480 and even then it still probably in a best case scenario is 20%

http://www.anandtech.com/show/4008/n...rce-gtx-580/15

This is the very best the 6870 does against the gtx 480 and this situation is particularly CPU limited because it is an old game(e.g SLI 580 performs more or less the same as a gtx 580). Most of the time it is closer to 50%. In 3 out of the 10 games in anandtech's review, it was 70%(battleforge, hawx and dirt 2).

When the 6870 is losing to the gtx 580 in a game that loves AMD cards like battlefield bad company 2 by 48%, 30-50% doesn't look too good.
By quick calculations, GTX580 is 20-60% faster than HD6870 in those testes. So HD6970 at 50% more than HD6870 would most likely winning some and losing some. So basically it would about par in performance. Ofc it still has so much room to change depending on its architechtures improvement points. If they can improve lot in situations where GTX580 is strong, it could come at overall winner. But in other way also, it could come overall loser. Shame we need to wait so long..