Sustainable IT | Ted Samson » In AMD-Intel square-off, memory proves key

August 06, 2007 | Comments: (0)

In AMD-Intel square-off, memory proves key

TAGS: AMD, Energy conservation, Green technology, Intel, Processors

In a follow-up gauntlet of tests pitting Intel Xeon processors against AMD Opterons, independent research company Neal Nelson and Associates found the Opteron generally -- but not always -- delivers superior raw energy efficiency. Interestingly, server memory proved a key factor.

Nelson tested the Opteron against the Xeon last month and determined AMD to be, hands down, the more power-efficient chip. His tests and results sparked plenty of discussion, including in my blog, prompting him to perform follow-up tests.

The most significant difference between this and the previous test is that he used an Opteron 2222 CPU rather than the 8222. He stuck with the Xeon 5160. In his tests, he once again compared the energy efficiency of a couple of similarly equipped servers, both configured with 4GB and 8GB of memory, as they processed Web transactions at a variety of load levels.

When machines were configured with 4GB of main memory, the Intel Xeon-based server proved between 1.4 and 5.1 percent more efficient. However, at 8GB, the Opteron server was between 6.1 and 12.7 percent more power efficient.

"It appears that when Intel chips are installed in Intel motherboards and sold as Intel servers, the Intel claim of superior power efficiency is not supported by the empirical data," said Nelson in a written statement.

Notably, the AMD server equipped with 4GB of memory proved 33.3 percent more power-efficient in idle than the Intel; with 8GB, it was 43.4 percent more so.

Power consumption is relevant in idle mode, Nelson notes in a release about this round of tests, "since many servers spend most of their time waiting for work." He cites Robert Frances Group's finding that the average utilization of most processors in a datacenter is between 15 and 20 percent.

In the previous test, the AMD-based server consumed 7.3 to 15.2 percent less power at five different user load levels and 44.1 percent less power while the systems were idle and waiting for work, Nelson reported.

Nelson used the same testing benchmarks in this test as he did in the previous one: He processed a series of Web transactions on both servers, which were running Suse Linux Enterprise Server from Novell, Apache2 Web server software, and MySQL relational database.

However, in this series of tests, he used an Opteron 2222 instead of the 8222 as in the previous matchup. "AMD offers a '2 socket' version of the Opteron as a model 2222. It has the same cache and frequency specifications as the model 8222, but the 2222 is limited to motherboards with a maximum of 2 sockets, and it is less expensive than the model 8222," according to Nelson's test report.

The performance differences between the two were negligible; generally, the 8222 was around 1.5 percent more efficient than the 2222.

In terms of cost, Nelson estimates that the 8GB configuration of the Xeon server would sell for about $4,651; the Opteron system would cost approximately $4,252. With 4GB of memory, the Xeon machine costs around $4,277 and the Opteron, $3,961.

For more information or to download a copy of the white paper outlining the test and results, go to worlds-fastest.com.

Posted by Ted Samson on August 6, 2007 01:37 PM

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