If you pardon the pun, power continues to be a hot topic in the world of computer servers. The costs associated with operating and cooling an average server are certainly not cheap, and these costs continue to rise over time with higher performing and higher power parts being released. Low-voltage processors try to reverse that trend, although they are only truly effective at halting the CPU power requirements. Unfortunately, the CPU is just a piece of the puzzle. Memory, fans, chipset, drives, HBAs, etc. all play a role in power requirements, and in some of those areas (FB-DIMMs in particular) the increase easily overshadows the power savings associated with low-voltage processors.
In our previous article that compared Intel dual-core parts to AMD dual-core parts, AMD came out on top. The main reason for their victory is their power consumption figures. The Intel dual-core Xeons compete on a performance basis, but FB-DIMMs hurt overall performance/watt numbers. In this article we see the tables turn somewhat. With two extra cores the Intel Clovertown parts are able to easily outpace the AMD Opteron, at least when overall load is near saturation. At low to average workloads, there is little difference between any of the parts, in which case server consolidation might be a better solution. Obviously, the quad-core parts are best suited for loaded database servers and their sweet spot is in virtualized environments.
If there was ever any doubt that Intel made a bad decision not going true quad-core, it should be clear with numbers like these that their decision was sound and is paying off. Quad-core processors may not be faster in every situation, but in heavily threaded CPU intensive environments the extra CPU cores are easily able to make up for any penalties associated with the dual-die packaging.
This is not the end of the story, however. The next few months should prove interesting for the two processor giants, as AMD's Barcelona should begin to show up in volume and Intel is set to refresh their Xeon line-up with Harpertown. Stay tuned; we'll have thorough coverage for both products in the near future.