It will be interesting to see if this expectation turns out to be true.
We heard similar claims before Prescott came out. It was to be the performance leader. Look how that played out.
I believe Merom/Conroe/Woodcrest will be performance per watt leader when compared at the same frequency to A64/Opteron, but I believe it will lag A64 in frequency and overall performance.
If I'm wrong, I'll simply sell my AMD stock at that time. No need to get worried now about something that is 7-9 months away.