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IBM tops Green500 supercomputer list

Big Blue supercomputers are among world's most energy-efficient, says, with top honors going to a system in Poland built on a BladeCenter QS22 cluster.

Big Blue's supercomputers are among the greenest in the world.

An IBM supercomputer won first place in a new list ranking the world's most energy-efficient supercomputers.

The June Green500 list, announced June 30 and published by, also showed that 18 of the top 20 greenest supercomputers in the world are made by Big Blue.

The group also said that the average efficiency of the supercomputers rose by 10 percent, even as the aggregate power of the machines on the list increased 15 percent.

A key factor in determining a supercomputer's energy efficiency is the number of operations per watt.

Winning the title as most energy-efficient system was an IBM supercomputer based on an IBM BladeCenter QS22 located in Poland at the Interdisciplinary Center for Mathematical and Computational Modeling at the University of Warsaw. The computer produces more than 536 Mflops (millions of floating point operations per second) per watt of energy.

The world's fastest supercomputer, the IBM supercomputer at Los Alamos National Laboratories, came in fourth for energy efficiency, producing over 444 Mflops per watt of energy.

"Modern supercomputers can no longer focus only on raw performance," said David Turek, vice president of deep computing at IBM. "To be commercially viable these systems most also be energy efficient. IBM has a rich history of innovation that has significantly increased energy efficiency of our systems at all levels of the system that are designed to simultaneously reduce data center costs and energy use."

The Green500 group also noted that the No. 5 supercomputer, GRAPE-DR of the National Astronomical Observatory of Japan, is "arguably" the first on its list with more than a million processing elements--in this case, 2.1 million.

Unveiled in 2007, the Green500 list is published two to three times a year by It typically serves as a follow-up to the Top 500 list of worldwide supercomputers announced by In the most recent Top 500 list revealed last month, the Los Alamos supercomputer built by IBM hit a peak performance of 1.105 petaflop/s (quadrillions of floating point operations per second).