The next-generation prototype of IBM's Blue Gene, Blue Gene/Q, has topped the latest iteration of the , a ranking of supercomputers by their power efficiency, released today at the SC2010 conference in New Orleans.

Blue Gene/Q is 165 percent more efficient than the Chinese supercomputer, Tianhe-1A, that topped the , released Sunday. It is 77 percent more power-efficient than the number-two entry on the Green500 list, the Tokyo Institute of Technology's Tsubame 2.0.

In terms of raw numbers, Blue Gene/Q was shown to execute 1,684 megaflops per watt. Tsubame 2.0 demonstrated 948 megaflops per watt, and the EcoG system from the U.S. National Science Foundation's National Center for Supercomputing Applications placed third with 933 megaflops per watt.

The list shows that the most powerful supercomputers may not be the world's most efficient users of energy. Blue Gene/Q, for example, demonstrated a peak performance of only 653 teraflops, a small number compared with Tianhe-1A's 2.57 petaflops. However, Tianhe-1A only demonstrated an efficiency of 635 megaflops per watt, and placed tenth on the Green500.

Virginia Tech researcher Wu-chun Feng created the Green500 in 2007 as a way to draw attention to the growing energy consumption in supercomputers. "We consider [energy use] to be a first-order design constraint," Feng said in an interview with the IDG News Service.