Things will get quite interesting when it comes to power consumption, as AMD is introducing the PowerTune technology, which enables dynamic overclocking and downclocking of the graphics card in order to achieve smooth gaming performance. This technology also altered the way how GPU power consumption is measured, bringing the maximum TDP up to 250W. AMD claims that TGU or "Typical Gaming Power" will not exceed 190W but the company placed an 8-pin and a 6-pin connector on the board, meaning you have up to 300W to play with. Our sources claim they already saw GPU overclocked to 1GHz+ speeds, meaning that Cayman can really stretch its legs.
Performance-wise the cards will not be able to best NVIDIA's GeForce GTX 580. According to AMD's marketing department, the AMD Radeon HD 6970 is somewhat faster than the GeForce GTX 570, while the Radeon HD 6950 is "in a class of its own" somewhere between the GeForce GTX 460 and GeForce GTX 570. Interestingly, AMD also promises better CrossFireX scaling.