Well we aren’t allowed to break NDA with our own results, but Fudzilla has posted some 3dmark 11 figures they have achieved with a HD6970 and a GTX580.
“We have compared the 3Dmark data we acquired from a source with our own that we got on a similar configuration. In 3Dmark 2011 Radeon HD 6970 scores slightly lower than 8000 at entry settings while the GTX 580 scores 8700 in that same test. The runner up, GTX 570, scores slightly above 8000 while the GTX 480 is slightly below 8000.
At performance settings Radeon HD 6970 a.k.a. Cayman XT scores around 5300 while the GTX 580 scores are just tad below 6000 and the GTX 570 loses by an inch with 5250 score. GTX 480 scores almost identical to the GTX 570, its 5250 points are again slightly lower than HD 6970.”
KitGuru says: So there you have it, HD6970 is markedly slower than the GTX580, although it should also be significantly cheaper also.