3dmark 11 results can favor AMD more than real world gaming. In games the 7970 is only 11% on average faster than gtx580 in DX11 mode and 2% faster in DX9 /DX10 mode.
This puts the 7950 on par with the gtx580 in real world performance at best.
Hmm, really? That's not what this says:
http://www.hardocp.com/article/2011/12/22/amd_radeon_hd_7970_video_card_review/14
Stock 7970 vs Factory OCed GTX580: 9-29% faster among 5 modern games for a single display, and 16-38% faster for eyefinity in same tests.
When overclocking the 7970 (still at stock voltages), they came up with this:
http://www.hardocp.com/article/2012/01/09/amd_radeon_hd_7970_overclocking_performance_review/7
Which increased its lead over the factory OCed GTX580 to anywhere from 33-62%.
Maybe they got a great OCer, but either way it's pretty compelling evidence that the 7970 is faster than the 580. If not, there are a lot of foolish people overpaying for 7970s considering what a 580 can be had for.
