China is experiencing a supercomputing boom.
For the past two years, the country has been home to the world's most powerful supercomputer, the National University of Defense Technology's Tianhe-2 machine. But China's prowess at building supercomputers is becoming widespread.
China now hosts 109 of the high-performance computing systems on a widely watched list of the world's most powerful supercomputers that was released Monday. The country had just 37 machines on the list only six months ago.
The U.S. remains home to the largest number of supercomputers on the list, but with 200 machines, the U.S. tally has fallen to its lowest level since computer scientists began compiling the list, called the Top500, back in 1993.
The U.S. is slipping on the Top500 list even as the country performs an unprecedented build-out of high-performance computing. Over the past decade, companies such as Alphabet Inc.'s Google, Amazon.com Inc. and Facebook Inc. have spent billions building massive data centers that operate as supercomputers for the Internet. These systems, however, aren't optimized for the type of calculations that the Top500 list's benchmarks test for.
The results don't reflect so much a slowdown of U.S. supercomputing efforts as an acceleration of high-performance computing build-outs in China, said Horst Simon, deputy director of the Lawrence Berkeley National Laboratory.
"China has recognized the value of high-performance computing for modeling and simulation and has ramped up simulations and created a broad base of installations that is very competitive with the U.S.," Mr. Simon said.
The Top500 results are important because they serve as a shorthand way of viewing international competitiveness in computer simulations. Originally used for scientific modeling in physics and chemistry, these systems are increasingly used to simulate consumer products—everything from automobiles to diapers.
Tianhe-2, which has been ranked the world's most powerful supercomputer since June 2013, is capable of performing 33.86 quadrillion calculations a second. The system ranked second on the list, Oak Ridge National Laboratory's Titan, can perform 17.59 quadrillion calculations a second.