Prescott is not necessarily a valid indicator of 90nm thermal performance. Again, look at Dothan for a better indicator... As It's not a radically reworked system like the Prescott is.

90nm = overclocking king ?

It looks like AMD has taken a move from Intel's playbook with their the transition from 0.18 to 0.13. Intel first tested the 0.13 process on the P3 Tutitans(sp?), before utillizating on the P4(Northwoods).

It probably is being released in the low end first because it uses the .09 version of the Winchester? core that only has 512K L2 cache on it instead on 1mb. If it's smaller at .13 than most current chips, it will be even smaller at .09. The new process makes alot of lower speed bin A64s and Semprons alot less expensive for AMD to produce if the new manufacturing process has flaws still that need to be worked out.

It's very smart to move the volume products to 90 nm first. While it's not clear what clock scaling might be like at 90 nm, it's a sure bet that you'll be able to get more chips per wafer at 90 nm. The more chips/wafer benefit dovetails very nicely with the volume processor market strategy. It's all about the shareholders. AMD is maturing, and they need nice stable profit growth, not cowboy risk-taking.