K Computer Still the Most Powerful Supercomputer

Japan's K Computer defended its number one spot in the new Top 500 ranking of the world's most powerful supercomputer, increasing from 8.162 petaflops to 10.51 petaflops per second.

John Rath

November 14, 2011

2 Min Read
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The K Computer from Japan, shown above, has retained its title as the world's most powerful supercomputer in the new Top 500 rankings released earlier today.

The newly-released Top 500 list of the world's most powerful supercomputers finds Japan's K Computer defending its number one spot, increasing from 8.162 petaflops to 10.51 petaflops per second (10.51 quadrillion floating-point operations per second). The letter "K" is short for the Japanese word "kei," which symbolizes 10 quadrillion.

A Familiar List

On the June Top 500 list, the K computer took the number one spot away from China's China’s Tianhe-1A system, which remains in the number two spot at 2.57 petaflops.  With the Oak Ridge National Lab'ss Jaguar supercomputer at number three, the rest of the 38th edition of Top 500 list looks pretty familiar. "This is the first time since we began publishing the list back in 1993 that the top 10 systems showed no turnover," said TOP500 editor Erich Strohmaier, who will lead the discussion at SC11.

10 Petaflops on the way to 23

Installed at the RIKEN Advanced Institute for Computational Science (AICS) in Kobe, Japan in partnership with Fujitsu, the K Computer uses 705,024 SPARC64 processing cores, which is more than the rest of the top five on the list combined.  Four times more powerful than its nearest competitor, the K Computer uses 12.66 megawatts of power, compared with 9.89 megawatts reported in June.  It is however still one of the most efficient supercomputers on the list though, delivering 830 Mflops/watt.

The K Computer was installed in 672 racks in June and an expansion to 800 cabinets allowed the 10 petaflop achievement to be accomplished. A week ago Fujitsu announced the expansion possibilities for the K computer as it could grow to a theoretical 23 petaflops.

Power and Performance

Although the rankings are unchanged, other characteristics evolved with the November 2011 list.  The entry point for being on the Top 500 list is now 50.9 teraflops, and the combined performance across all 500 superomputers is 74.2 petaflops, up from 58.7 petaflops last June. Used in 223 systems, Gigabit Ethernet is still the most-used internal system interconnect, but InfiniBand use increased to 213 systems. As the average power consumption continued to rise, 29 of the systems on the list are now confirmed to use more than one megawatt of power. The most energy efficient supercomputers are BlueGene/Q with 2,029 Mflops/watt. IBM recently filed a patent for a massive supercomputer that could reach 107 petaflops. Of those systems reporting on power the total consumption of the 500 systems is more than 159 megawatts.

"The road to Exascale" is a frequent article title when talking about the future of supercomputer systems and with that goal in mind, large efficiency gains will be front and center for manufacturers, to avoid needing gigawatts of power.

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