Nice review W1zzard. Lots of work with dynamic clocks and such.
So my thoughts:
Based on my calculations (by specs) and a lot of assumptions (such as efficiency loss) I predicted it would be 25% faster than GTX580 @1080/1200p a long time ago and it is indeed 25% faster. It's really intriguing, to say the least, because of the many factors that I took into account in order to reach that conclusion/guesstimate, but I'm amazed and overly happy with the result, because it means that this is a win for science. (I know it's kinda arrogant after the fact, but I'd really like to hear from all the people that called me crazy, fanboy and whatnot in the threads related to specs, where I made those predictions, but I know most of them were new users and we will never ever hear about them on TPU).
However the most intriguing factor is that the performance lead over the GTX580 is bigger at 2560x1600, and that's something that I'm sure nobody would have predicted. HD7970 being comparatively faster at 1600p is not a surprise though. Also, according to [H] it looks like the performance lead over the HD7970 is also bigger on multi-monitor, which is again a big surprise.
But all things considered, I still think these cards are not really a worthy upgrade until they come close to $400.