A personal record of understanding, deciphering, speculating and predicting the development of modern microarchitecture designs.

Monday, September 10, 2007

Scalability counts!

As I have said in this article, Intel's new Core 2 line of processors have good cores but poor system architecture. The poor scalability of FSB means that Core 2, without extensive, expensive, and power-hungry chipset support, is only suitable for low-end personal enjoyment.

Take a look at this AnandTech benchmark. I'd note foremost that AnandTech is hardly an AMD-favoring on-line "journal"; thus we can expect its report to be at worst Intel-biased and at best neutral (which I'm hoping for here). In any rate, the benchmark picture is reproduced below:

The comparison between Barcelona (Opteron 2350 2.0GHz) and Clovertown (Xeon E5345 2.33GHz) couldn't be clearer: FSB is an outdated system architecture for today's high-end computing, and scalability does matter for server & workstation grade performance. While AMD's quad-core Opteron at 2.0GHz is slower than Intel's quad-core Xeon at 2.3GHz on single-socket test, the situation is reversed when going to a dual-socket setup, one that used by most workstations and entry-level servers.

The same phenomenon is also observed in this page where AMD's quad-core Opteron, at 17% slower clock rate, performs increasingly better than Intel's quad-core Xeon with more number of cores (picture reproduced below). Again, when it comes to server & workstation performance, scalability counts.
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