Barts seems to be the best bits from 58xx and 57xx range of cards with extra tessellation performance and a couple extra features. The result is a 6870 that falls squarely between the 5850 and 5870 performance wise on a smaller chip, which results in lower production costs. If AMD has been able to refine the architecture this much over the previous generation, Cayman is going to be powerful, and Antilles is going to be a monster. AMD shouldn't have to break the 300watt standard to hit their target performance range.

Seriously, they released the 68xx series of cards as a teaser of what's to come. They know they've got something special with Cayman, and they just want to make us drool a little before releasing it. Hype is the most powerful selling factor behind a product, and it cannot be bought for any price. AMD has it at the moment, and Nvidia is trying to keep it down by announcing the GTX 580 and releasing a bugged benchmark that uses stupid amounts of tessellation.

Yeah, I'd say AMD/ATI is the game changer at the moment, and Nvidia is playing catchup. Nothing like having 90% of the DX11 card market locked up.