Chipguy:
Easy. AMD's is for maximum possible power usage and Intel's is for typical power usage. At the same standard, they are closer together. Then you add in the NB portion of the chipset, the 4 FB-DIMM controllers and a mininum of 4 more AMBs and you'll likely exceed 80 more maximum possible watts. Then 80+80+(>80) > 120+120. Push it with 12 more AMBs and Woodcrest spins the KW meter a whole lot faster.
Then while 8 Opteron SEs are gluelessly in a server, you need 4 complete 2 way Woodcrests to match. Thats more FB-DIMM controllers, more NBs, more interconnect, lots more AMBs, more controllers, more drives, etc. And 4 2 way Woodcrests don't work as well as 1 8 way Opteron. Woodcrest clusters don't scale as well either. And that is before K8L, before cHT 3.0, before chassis interconnect, before coprocessing and other things that are coming down the pike.
A simple 1207 Clearspeed FPGA and boom, Woodcrest loses with program specific integer processing and program specific FP processing. A Opteron 2220 SE and Clearspeed 1207 leaves 2 way Woodcrest in the dust when a suitable FPGA configuration accelerating the inner loop of the target program is used. The Opteron Clearspeed benches in 1 unit of time and the dual Woodcrest takes 45 units. Using that application, isn't the performance/power of the former far higher than the latter? This is from Clearspeed claims.
HPC benchmarks also show that Opteron has far higher interconnect BW and far lower latency than Woodcrest. It also scales much better.
And to answer AMD announces "an upgrade path" in the headline, because the Rev F product itself is so underwhelming.
What is clear is that Woodcrest itself it so underwhelming for the 4 way and up market. Intel had to pre announce a QC. They even had to release yet another Xeon MP based on the hot and slow P4 because Woodcrest is so underwhelming. And Intel has absolutely nothing for the 8 way AMD64 market. Intel knows how bad the overall performance will be when they stick four NGA cores on a single FSB. Can you say BOTTLENECK?
Pete
