Performance Expert Says AMD Beats Intel on Quad-Core Server Efficiency

Published: February 5, 2008

by Alex Woodie

Servers based on quad-core processors from AMD are considerably more efficient than servers based on quad-core processors from Intel, even though the Intel processors themselves are slightly more powerful and may even be more efficient, according to Neal Nelson, a group that analyzes computer performance. The reason for this apparent paradox in power consumption may not be immediately obvious. But here's a little hint: It's the memory.

According to the results of 57 power efficiency tests Neal Nelson's group performed, servers based on quad-core Xeon chips from Intel delivered, on average, 14 percent more throughput compared to similarly equipped servers loaded with quad-core Opterons from AMD. However, the Opteron-based servers consumed an average of 41 percent less electricity than their Xeon counterparts, the group found.

"By themselves, the Intel processor chips may use less power," says Neal Nelson, who designed the tests. "But all current Intel Xeon servers require the use of fully buffered memory modules. These FB-memory modules appear to consume more power than the DDR-II memory modules used by the AMD-based servers. The result is that in many cases an Opteron-based server actually uses less total power than a Xeon-based server."

The tests were conducted last summer using servers loaded with 4 GB, 8 GB, and 16 GB of main memories, in 1 GB chunks. Servers with the most memory had the biggest power-consumption discrepancies when using the two different quad-core chipsets, further backing up the fact that it's the memory, not the chips, that dictate which processor architecture can lay claim to being the most efficient, according to Nelson.

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