The top single-GPU of a new generation usually beats/matches the double-GPU of last generation in performance and heat/power, with almost same price of the last gen single-GPU. It has been the rule of thumb in the past.

When AMD chooses to play nVidia's number-game in this round, then Cayman should beat the 5970 in performance and heat/power usage, with almost the same price of 5870 . If they can do that, then it's a good move, but that's going to be hard on the same 40nm node.

It will be inserting to see if they can pull off a "new generation" successfully, or it will be a re-fresh, re-brand, or evelution.