Database Server CPU Comparison: Athlon MP vs. Hyper Threading Xeon

Final Words

Before we get into the meat of the conclusion, let's have a quick recap of the performance improvements we saw when going from single to dual CPUs and when toggling Hyper Threading (on the Xeon 2.2 CPUs):

What the above tables show is that in spite of the Athlon MP's point-to-point connection to the North Bridge, MP scalability is still not dramatically improved over the shared bus used by the Xeon. In fact, in the Web DB test the Xeon scales much better than the Athlon MP, possibly because of more overall memory bandwidth. We've said it before but it is worth repeating especially now, the Athlon MP needed a dual channel DDR chipset for the enterprise market. Because NVIDIA would never think of bringing nForce for the validation nightmare known as the enterprise market, AMD probably figured that they would be better off waiting for Hammer to introduce a higher bandwidth memory solution for the enterprise market. It saves them the costs of producing and validating an even more complicated chipset that would be replaced by a simpler Hammer solution in a couple years time.

The other thing to take away from these tables is that Hyper Threading does have a great deal of potential. In our most stressful database server test, it improved performance by 17%. For a feature that takes up such a small percentage of the overall die size, it's not bad at all. These tests also show that the performance improvement of Hyper Threading is not always predictable. In the Web and Ad DB tests, the performance change varied from an increase of 3% to a decrease of 5%. You'll remember from our descriptions that both of these tests were heavy on the selects. The more varied benchmark was the Forums DB test and that's where we saw the largest overall improvement that Hyper Threading provided; it also happened to be the benchmark that the Xeons with Hyper Threading disabled did the worst in.

Over the past few months we've had many OEMs approach us asking about a comparison between the fastest Athlon MPs and Xeon processors in a true server environment; well, it doesn't get much more real-world than this.