Xeon 2.8GHz DP & 2.0GHz MP - Part I: Taking over the Enterpriseby Anand Lal Shimpi on November 18, 2002 9:04 AM EST
- Posted in
- IT Computing
For our final Web DB test we crank up the load to 12 times that of the original Web DB test, for a total working database size of almost 3GB; for a content-only database, 3GB is quite a few reviews. It is here that we separate the boys from the men and the benefits of 4-way SMP and Hyper-Threading really become clear.
First off, the 4-way Xeon MP maintains a 64% performance lead over the 2-way Xeon DP courtesy of the number of CPUs. It's interesting to note that even under such heavy load, the 2-way Xeon MP is not able to overcome the clock speed deficit and outperform the 2-way Xeon DP. This could be an indication of why Intel didn't want 4-way configurations of their 2.8GHz Xeon DP processors as they could theoretically outperform the more expensive 4-way Xeon MP solutions.
In this test we see that the benefit from going to 4 processors is a healthy 88%. However you must realize that it took us multiplying the load on the server by a factor of 12 before we got this sort of scaling with CPUs as well as this sort of performance advantage over the 2.8GHz Xeon DPs.
Hyper-Threading proves to be most useful here, providing a 35% performance gain for the 4-way Xeon MP solution and a 33% gain for the 2-way Xeon MP. The Xeon DP setup received a smaller 27% performance boost. This is the second time we saw a more impressive performance gain out of the Xeon MP parts than the Xeon DP and it could be related to the fact that the Xeon MP CPUs have more cache to share amongst the multiple threads contending for resources. We would assume that there's a reasonable deal of locality in these concurrent memory accesses but this data may indicate otherwise.
In either case, Hyper-Threading definitely proves its worth here; although not as effective as moving to a 4-way configuration, Hyper-Threading offers more bang for your buck than adding more cache or even increasing clock frequency - the combination of all three however, results in a much more powerful server microprocessor.