Whew, didn't mean to rile people up with my response, but usually most reviews I've seen show a 25+% gap between 5870 and 480 @ 2560x1600 (which is the only resolution I really watch nowadays and have for awhile), ESPECIALLY in crossfire/sli modes with two cards it's even wider. I could be wrong, and if I am misremembering the reviews, just carry on to my next paragraph...

My figures may be off a bit, but if Cayman XT is for argument's sake 10% slower than a 580, I would expect it to be more than 10% off of the 580's price overall (more like 15-17% less) since they need a bigger incentive to settle for less (same goes for if Cayman XT is faster than the 580, of course...). The top card always carries a bigger premium in respect to price/performance, and I expect amd/nvidia will capitalize on that whichever way the pendulum swings here.

P.S. I'm in for 2 of whichever is faster... . Frankly I'd love for them to come in nearly even, and spark off some nice price cuts.