HD 6970 Tessellation
According to this slide, the upcoming Radeon HD 6970 (launch planned for December 13, 2010) will be around twice faster in tessellation than the Radeon HD 5870. In the best case with a tessellation factor of 8, the HD 6970 is 3X faster than the HD 5870. In TessMark (moderate mode), the HD 5870 reaches 27000 points (450 FPS). We can expect a score of around 81000 points (more than 1300FPS) for the HD 6970. If this statment is true, that means the HD 6970 is faster than the GTX 480 or the GTX 580 for a tessellation factor of 8X. Nice!
HD 6970 Power Containment
According to the following slides, HD 6900 series seems to have a fine grained power control feature that allows to control the power draw every GPU clock cycle: