beamer -
I'm not in the benchmark business and publishing my data would be a violation of my client agreements. In the testing I performed, Nehalem wins some, Shanghai wins some. I have said that I don't think the dynamics are likely in themselves to shift server share - those who chose AMD for specific workloads will probably stay with AMD, those who have an investment in Intel have every incentive to stay on that path.
During the course of my 6 month characterization of Nehalem and Shanghai, I got three refreshes of Nehalem, each better than the last. Raw performance is stunning and real world performance on many workloads is also very good. As I said previously, I saw performance between 170% and 200% of Harpertown in several tests.
But before we consign Shanghai to the dustbin of history, let's look at a few areas where it has an edge over Nehalem. Remember that big IT shops don't have the luxury of green field development very often, especially in these tough times.
One example is expanding existing virtual farms where peak loads are moved to faster machines and lower utilization loads are moved to less powerful machines. Loads are moved dynamically, based on usage prediction. So if you have say 10 servers in a pool and you want to maintain peak response as the load grows, ideally you add a few more high power boxes, move the critical loads to those boxes dynamically, which gives better response while lowering the load on the existing pool. While Nehalem looks like a good bet for peak load management, the problem is that you can't take your existing servers and pool them with Nehalem - the servers need to be in the same family (or the VMs need to be lowest common denominator, which defeats the purpose).
So the choice for Intel architecture in that scenario is Dunnington, not Nehalem.
With AMD, live migration is possible back to Barcelona and forward at least through the Istanbul products and probably the MCM product as well. Someone who has a mix of Barcelona and Shanghai servers not only has the architectural barrier (can't shift to Intel without replacing the whole pool), they also have a reasonable upgrade path, at least for the next year.
Core 2 was a pretty good product - so people who chose AMD over the last 2 years did so not based on raw performance, but because of something it did better than the Intel part, and Nehalem probably doesn't change that, at least in the enterprise space. For those doing a ground up project or fork lift upgrade, Nehalem is obviously a great choice.
