The sixth edition of the Green500 List shows a continuing improvement in energy efficiency among the world's fastest supercomputers.

Three IBM QPACE (quantum chromodynamics parallel computing on the Cell) top the latest Green500 list, all tying for first place and all are located in Germany: Jülich Research Center, University of Regensburg, and University of Wuppertal.

The low-power QPACE clusters use the IBM PowerXCell 8i processor, an enhancement of the Cell Broadband Engine originally developed by Sony, Toshiba, and IBM for Sony’s PlayStation 3. Additionally, each QPACE cluster further improves its performance-per-watt by connecting its processors via a network of programmable units called Field Programmable Gate Arrays, said Green500 co-founder Wu Feng, an associate professor with the Virginia Tech College of Engineering computer science and electrical and computer engineering departments.

The latest rankings also represent the largest absolute megaflops/watt increase to 722.98 megaflops/watt from 536.24 megaflops/watt, Feng said. “IBM continues to lead the pack in energy efficiency with three 722 megaflops/watt systems. The new IBM QPACE system improves upon the most energy-efficiency supercomputer from the June 2009 list by 35 percent.”

Since its 2007 debut, the Green500 has ranked the energy efficiency of the world’s 500 fastest performing supercomputers. The list serves a complement to the TOP500, providing a foundation for tracking trends in green supercomputing. Megaflops equal mega floating-point operations per second, Feng said.

Machines on the Green500 consistently are becoming more energy efficient. “During the past year, the average megaflops/watt for machines on the Green500 increased by 27 percent,” Feng said. “The implication here is that, as a community, we are indeed building more energy-efficient supercomputers.”

The focus of performance-at-any-cost computer operations has led to supercomputers that consume vast amounts of electrical power, Feng said. As a complementary viewpoint, the Green500 highlights those supercomputers that place a high premium on energy-efficient performance for sustainable supercomputing, without jettisoning operating speed.

“We cannot afford to continue building new power stations to support such resources,” Feng said. “We need to be more efficient at all scales of supercomputing.”

Meanwhile, for the first time in the Green500’s history, the maximum aggregate power consumption, which currently comes from the United States, decreased to 122.9 megaflops/watt from 125.6 megaflops/watt, while the average aggregate power consumption remained level. “The world's supercomputing power is now more evenly distributed among countries and machines are becoming more energy efficient,” Feng said.

The November 2009 list comes just weeks after Feng announced a refresh to the two-year- old compilation of the Green500 that expands its outreach. In a year’s time, Feng says he hopes that the Green500 list “will start to become more prominent because it attempts to broaden the scope of supercomputing and put an additional focus on energy efficiency.”

The Green500 List is released twice a year in June and in November.

Share this story