Multi-Tasking

In this section we performed a few tests aimed at revealing the systems performance when there are a few applications running simultaneously. We launched several resource-hungry tasks in different applications and measured the time it took the test platforms to complete them.

Here we were processing an image in Adobe Photoshop and at the same time compressing a folder with files using WinRAR utility. The results are quite common already: Quad FX platform is faster than any dual-core processors, but loses to Intel?s quad-core CPUs on Core micro-architecture.

Then we were editing video in Adobe Premiere Pro and encoding an MP3 file using Apple iTunes. And here, finally, AMD?s dual-processor system with two 3.0GHz CPUs managed to outperform a quad-core Intel processor working at 2.4GHz.

The third test is probably the most sophisticated. Our test platforms were busy working on three tasks at a time: image editing in Adobe Photoshop, final rendering in 3ds max and video encoding into MPEG4 format. Here Quad FX platform performed not so well falling behind Intel?s dual-core CPUs. Moreover, as we see, the dependence of Quad FX performance on the CPU frequency is quite small, so I would assume that there is something limiting this performance dramatically. But of course, it is high latency of the memory subsystem, which we have already complained about several times.

Besides the performance of the dual-core and quad-core platforms running several parallel tasks, we also decided to investigate the influence of background processes on the performance in certain resource-hungry applications. We measured the fps rate in Quake 4 game with several copies of WinRAR utility running in the background.

We have finally found the strength of the Quad FX platform that actually originates exactly from the server side. We can see that as the number of simultaneously processed tasks increases, Quad FX platform starts outpacing Intel based systems. And this is quite logical, actually. Sooner or later Intel processors use up the entire bandwidth of their memory subsystem that serves for data transfer between the Kentsfield core pairs that have no shared L2 cache. Quad FX platform features two independent memory controllers in two CPUs and hence features twice as high memory bandwidth. Therefore, Quad FX turns out more efficient than a much faster quad-core Intel Core 2 Extreme QX6700 once the multi-threaded workload increases dramatically.

Although we have to admit anyone will rarely have five or more resource-hungry applications running at the same time. Therefore, this advantage of the AMD Quad FX platform can hardly be determinative for common users.