SiCortex, which in September introduced what is arguably one the most energy-efficient high-performance computers, today is expected to introduce the Green Computing Performance Index (GPCI), a tool to rank the "greenest" computers.The GPCI calculates rank based on a range of performance metrics relative to energy consumed, instead of relying on a single benchmark result/watt. The GPCI is based on the industry standard HPCC benchmark suite, covering 23 benchmarks. The GPCI, says SiCortex, is the next step beyond the Green500, developed by Dr. Wu-chun Feng of Virginia Tech and colleagues, and based on the Linpak benchmark. The Green500 provides a ranking of the most energy-efficient supercomputers in the world.

SiCortex's most recent high-performance computer, the SC072-PDS, uses 72 processors -- but less electricity than a single PC and plugs into a standard wall outlet. "It uses 300 watts. That's less than a hair dryer," says SiCortex CEO Chris Stone, adding that SiCortex's strategy is to improve the energy efficiency of a system, rather than concentrate on cooling an already-heated data center.

Not surprisingly, SiCortex systems have performed well in GPCI rankings, says Stone. Still, on some line-item benchmarks, it's not always the most efficient. "That just shows you we have more work to do," he says.

SiCortex is posting the GPCI online in spreadsheet form. That way, says Stone, anyone wanting to compare systems using different regressions can do so. "We've come up with a way of measuring on a weighted or normalized basis. But if you don't like the way we did it and want to plug in whatever number you come up with, you can," says Stone.

Data center managers and computer vendors are being encouraged by SiCortex to run the full HPCC benchmark suite and post results and energy data on the HPCC Challenge Web site, which is sponsored by the U.S. Department of Energy, the National Science Foundation, and the U.S. Defense Advanced Research Projects Agency (DARPA).