China's Tianhe-2 Still World's Fastest Supercomputer

The latest Top500 list shows a continued slowing of overall performance growth, though that could change in 2017.

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China's massive Tianhe-2 supercomputer is still the world's fastest, topping the latest list of the top 500 more powerful systems.

This is the fourth consecutive time the Tianhe-2—developed by China's National University of Defense Technology—has been No. 1 on the Top500 list, which is released twice a year. The latest Top500 list was released Nov. 17 on the first day of the SC14 supercomputing show in New Orleans.

There actually was little change in the roster of the world's top 10 fastest supercomputers—the only change from the previous list released in June was in the No. 10 spot—and organizers of the list said in a statement that it illustrates a trend over the last two years of a slowing growth rate in performance in the supercomputer space.

The list is compiled by researchers at the Lawrence Berkeley National Laboratory, the University of Tennessee and a German company, Prometeus. According to the researchers, until June 2013, the fast growth of performance in the largest systems at the top of the list had balanced the relatively slower growth rate of those systems at the bottom of the list. However, they said, the little turnover at the top of the list over the past couple of years is an indication that the overall performance growth rate is slowing.

This slowing growth rate is seen most clearly by the performance of the last systems on the list, which has been slower over the past five years (about 55 percent) than between 1994 and 2008, when the annual growth rate for the No. 500 supercomputer on the list was 90 percent.

Another indication of the performance slowdown is the total combined performance of all 500 systems on the list. Since the Top500 list was last released in June, the combined performance has grown to 308 petaflops per second—compared with 274 petaflops in June and 250 petaflops in November 2013—which organizers said "exhibits a noticeable slowdown in growth compared to the previous long-term trend."

However, concerns over the slowing overall performance growth rate may be alleviated in the next two years. The U.S. Department of Energy on Nov. 14 awarded $325 million to IBM, Nvidia and Mellanox Technologies to build two new supercomputers that agency officials said will be five to seven times more powerful than current systems they will replace—which currently sit at No. 2 and 3 on the Top500 list.

When it is delivered in 2017, the Summit system at the Oak Ridge National Lab will replace Titan, which currently is the world's second-fastest supercomputer. The Sequoia system at the Lawrence Livermore National Lab—which currently is the world's third-fastest—will be replaced by Sierra. IBM officials said both new supercomputers will have peak performances of more than 100 petaflops; Tianhe-2 currently has a peak performance of just under 55 petaflops.