Intel: Performance per what?

The keynote from Intel president and CEO Paul Otellini at Intel Developer Forum didn’t offer much in the way of product news, but it did introduce a fresh obfuscatory term to the PC vendor vernacular: Performance per watt. Most technology buyers, including those in IT, don’t know a watt from a kilometer. But those of us who are acquainted with the watt can’t claim bragging rights, for so few of us know what on Earth a “performance” is when offered as a unit of measure.

You can’t measure performance per watt (that’s Intel’s point), but you can make enough sense of the concept to know that it isn’t Intel’s strong suit now, and isn’t likely to be next year.

Using what’s shipping today as a point of reference, Intel’s latest single-core 3.33 GHz Xeon MP is a 136 watt part for 2-way servers. You must add to this the power consumption of the chip set’s north bridge controller, which provides the essential link between processors and memory, and between the processors themselves in a 2-way system.

AMD’s Opteron 875 with a pair of 2.2 GHz CPU cores is rated at 95 watts, and it’s an 8-way chip (sixteen cores per server max). There is no additional power burden for memory and inter-CPU traffic; independent controllers for these are built into each Opteron CPU.

To erase any doubt about AMD’s power efficiency chops, it has 30 and 55 watt Opterons in its product line today. The power requirements for AMD CPUs will plunge when AMD moves to .65 nm. AMD also built PowerNow! power management into Opteron, an advantage that Xeon doesn’t have.

If Intel succeeds in establishing performance per watt as a buying criteria, it’s picking yet another fight with a competitor that’s already an expert in server processor power efficiency. By this time next year, Intel’s 80 watt dual-core Xeon, strapped to its power-sapping legacy bus and memory architecture, with subpar (relative to 2006 Opteron) dynamic power control, will be nothing to brag about.