We decided to start our test session not with the applications that are typical of professional workstations, but with some classical benchmarks, which we usually use to test regular desktop platforms. It will allow us to get a better idea of the performance level contemporary dual-processor platforms may deliver not only in specific programs but also in desktop applications.
The results are pretty logical. PCMark05 test creates multi-threaded workload during work that is why the more logical CPUs there are, the higher is the overall system performance. This is actually the reason why Opteron 275 platform is faster than Opteron 254 platform. Xeon 3.6GHz system, just like the Opteron 275 system, boasts four logical CPUs. Even though Xeon 3.6GHz are single-core processors, they support virtual multi-core technology aka Hyper-Threading.
As for the results obtained on a platform with real dual-core Xeon 2.8GHz processors, its performance doesn’t look that great, according to PCMark05. This can be explained by the fact that these CPUs work at a pretty low clock frequency, which cannot be compensated by the ability to process eight computational threads at a time. The thing is that PCMark05 can create maximum four simultaneous threads. In other words, this benchmark cannot load a dual-processors system with dual-core CPUs supporting Hyper-Threading technology to the full extent.
We ca see almost the same situation in PCMark05 subtest targeted for testing pure processor performance. The only thing you should pay your attention to on this diagram is the victory won by the Xeon 3.6Ghz system. However, this is not an indisputable victory, because PCMark05 shows traditionally better results on Intel platforms.
When we tested the memory subsystems of the participating platforms in PCMark05, both Opteron and single-core Xeon systems demonstrated very close results. It seems to be quite natural, keeping in mind that the built-in memory controller of the Opteron CPUs works with dual-channel DDR400 SDRAM, while the memory controller of the Intel E7525 chipset used in our Xeon systems supports dual-channel DDR2-400 SDRAM with the same bandwidth.
However, if you have been reading our review attentively enough, you may wonder why we see no effect from the NUMA technology implemented in the Opteron platforms. A dual-Opteron based system seems to have four memory channels in total, doesn’t it? The thing is that PCMark05 test measures the memory bandwidth as a single thread, so you cannot see the advantages of the NUMA technology here.
As for the system built with dual-core Xeon processors, the low working frequency of its CPUs prevented it from performing as fast as its rivals in this test.