ATI RV610 and RV630 are 65 nanometre parts
 

Low/Mid-end range of ATI will be cheaper to produce and run cooler at 65nm

"They plan an April production of their 65 nanometre parts. Nvidia's G84 and G86 mainstream and low-end chips are still at 80 nanometre which means they get hotter and are more expensive to make. With good yields, DAAMIT has a good chance to come storming back to the desktop and mobile arenas.

http://www.theinquirer.net/default.aspx?article=37611

The high end R600 doesn't qualify as "power-friendly" at 250W+