InfoWorld review: Intel's Westmere struts its stuff

Fast AES encryption, better scalability, and consistent per-core performance make the new six-core Xeon a worthy successor to Nehalem

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I also ran specific tests on the new AES-NI encryption instructions. The results were very impressive. Using the same OpenSSL build with and without the AES-NI patches, AES encryption test cases showed a 400 percent performance increase. The test was simple: encrypt an 851MB file with the AES-256-CBC cipher. Without the AES-NI instructions in use, a Westmere X5670 CPU consistently completed this task in 13.5 seconds. When the AES-NI engine was used, the same task took only 3 seconds. That's huge.

A Westmere for you
The X5600 family is large, with 12 different Westmere-EP CPUs offering plenty of options. The X5650, X5670, and X5689 CPUs all boast the full complement of six cores running at 2.26GHz, 2.93GHz, and 3.33GHz respectively at 95 watts. The lower-cost E5620, E5630, and E5640s run four cores at 2.26GHz, 2.4GHz, and 2.53GHz respectively at 80 watts.

Westmere-EP also provides 40-watt options in the L5630 and L5609, whereas the lowest-power Nehalem-EP ran at 60 watts. There are also a few oddities, such as the 95-watt X5657 that runs four cores at 2.93GHz, and the 130-watt X5677 that runs four cores at 3.46GHz. The last two are optimized for lightly threaded workloads that can make use of the higher clock speeds, but don't need the additional cores.

If virtualization or highly threaded workloads are your game, the six-core models are definitely the way to go. If you're looking for raw clock speed on single-threaded workloads, the four-core models will give you better bang for your CPU buck. For the power miser, or those wanting to cram lots of lower-power CPUs into a rack, the 40-watt chips may be right up your alley. Essentially, there seems to be a Westmere chip to fit just about every scenario.

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