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Japan's 8-petaflop K Computer is fastest on earth

An eight-petaflop Japanese supercomputer has grabbed the title of fastest computer on earth in the new Top 500 Supercomputing List to be officially unveiled at the International Supercomputing Conference in Hamburg today.

The K Computer is based at the RIKEN Advanced Institute for Computational Science in Kobe, Japan, and smashes the previous supercomputing records with a processing power of more than 8 petaflop/s (quadrillion calculations per second) - three times that of its nearest rival.

Second place, and the fastest machine on the list when it was last published in November was the Tianhe-1A, built by the National Supercomputing Center in Tianjin, China, In the latest round-up, the Chinese machine achieved 2.6 petaflop/s.

The K Computer's success marks the first time Japan has claimed the number one spot on the Supercomputing Top 500 since November 2004, when NEC's Earth Simulator was dethroned after a two-year reign.

In contrast to many of other mega-machines in the list, the K Computer achieves the feat with not a single GPU in sight. The K Computer was built by Fujitsu, and contains more than 80,000 2GHz SPARC64 VIIIfx CPUs, each with eight cores, to deliver a total of more than 640,000 processing cores. An overview of the system is available here (opens in new tab) (PDF).

The K Computer consumes the most power - something, we'd imagine, in short supply in Japan at the moment - of any of the systems on the list. It draws a massive 9.89 megawatts. But given its gigantic processing output, it still manages to be the fourth most energy-efficient system in the 500, with a performance-per-watt rating of 825 megaflops per Watt. That compares to the average power efficiency among the 500 of 248 Mflop/W, up from 219 Mflop/W six months ago.

After the Tianhe-1A the rest of the top five, rated using the Linpack benchmark software, are the US Department of Energy's Jaguar computer from the Oak Ridge National Laboratory, at 1.75 petaflop/s; the Nebulae at the National Supercomputing Center in Shenzen, China, at 1.27 petaflop/s; and another Japanese computer, the Tsubame 2.0, at the Tokyo Institute of Technology, with 1.19 petaflop/s.

The first machine to break the petaflop barrier in June 2008, the Roadrunner from the US Los Alamos National Laboratory, now resides in tenth place.

For the full list of the Top 500 supercomputers, visit (opens in new tab). monitors all leading technology stories and rounds them up to help you save time hunting them down.