No they are not equiv. The woodcrest beats the opterons hands down in every test.
Can you point to one link on the web to back this up? I agree the 3.0GHz Woodcrests blow away the 2.0GHz Opterons, but the benchmarks I've seen show the 2.0GHz Woodcrests are on par with the 2.0GHz Opterons although the FB-DIMMs used by the Woodcrests show significantly poor memory performance relative to the DDR2 memory used by the Opterons making the Woodcrest perform poorer for intensive database applications.
Anyway, I'd really love to find out that I am mistaken about the Woodcrests. The only ones I see being offered in dedicated servers are the 2.0GHz ones and not the significantly more expensive 3.0GHz ones.
Go Woodcrest, as AMD is not likely to come out ahead of Intel now until quad cores start coming out.
There are several dedicated server providers that offer quad processor dual core Opterons now (for a total of 8 cores). Woodcrest is only offered in a dual processor dual core configuration. The Opteron servers scale better.
I agree that quad cores coming out in a few months will raise the bar again, but these chips will be expensive for awhile and I'm not sure if the Intel chip will support dual processor/quad core configuration. I think I remember that Intel is just slapping together two dual core processors on a single chip until the die shrinks again in a year or so.
Then again, processor power is probably not the bottleneck for your 8 core web servers since I/O and parallelization are probably the bigger issues. I've read that MySQL has a lot of problems in scaling to 8 cores to access a database since the lock implementation used causes many of the cores to spin wait. An 8 core database server is not necessarily 8 times faster than a single core server (as measured by the amount of transactions it can perform on a sustained basis).
The OP is getting a Dual processor server, not a quad processor server, therefore the Woodcrest is still the better option. Even in a quad processor server the Woodcrest is the better option and is available. The point I was making was that I believe (from personal experience) that Woodcrest and Conroe will have the dual core market at least until AM3 and the quad core chips come out.
Here are some benchmarks from the Woodcrest. While the server is dual processor dual core, the bechmarks still blow the AMDs out of the water, even the 2.0 GHz Woodcrests do.
Regardless, I am not interested in starting a CPU war. From my own personal experience and the benchmarks out there, as well as the price, Intel is winning right now, therefore if it were me I would use Intel.