I don't give a shit. A 6970 ran the Alpha fine with everything cranked except Ambient Occlusion and Bloom which I always turn off because I personally dislike them. Frame-rates were stable and in the high 60's and may have dipped to 50ish in town as I recall. Regardless, they were much smoother than 1.0. Alpha was an early build so I expect everything to tighten up and become better optimized as time rolls on. Regardless, compared to 1.0 it was like night and day. The 7970 recommended requirement is certainly a typo.

TLDR: Alpha ran great on my system. If you have a 5850 or above with any decent quad processor, you should be able to comfortably play 2.0.