WASHINGTON, D.C. – Two U.S. Department of Energy (DOE) national laboratories are now home to the fastest supercomputers in the world, according to the new TOP500 List, a semiannual ranking of the world’s fastest computing systems.

The IBM Summit system at Oak Ridge National Laboratory is currently ranked number one, while Lawrence Livermore National Laboratory’s IBM Sierra system has climbed to the number two spot. The announcement came today at SC18, the International Conference for High Performance Computing, Networking, Storage, and Analysis in Dallas, TX.

“Thanks to some of the brightest minds working at DOE’s national labs, America is leading the world in high-performance computing hardware, software, and applications as we move into the era of exascale computing,” said U.S. Secretary of Energy Rick Perry. “These extraordinary capabilities hold enormous promise for our country and will literally transform our leadership in science, our economy, and our nation’s security.”

Over the decades, DOE and its national laboratories have spearheaded America’s high-performance computing effort, which has been an important component of the nation’s overall competitive advantage globally. In recent years, the field has become increasingly competitive internationally, with the growing recognition of supercomputers’ extraordinary value as a tool not only of national security, but also of discovery and innovation.

In all, DOE national laboratories now house five out of the world’s ten fastest supercomputers. In addition to Summit and Sierra, they include Trinity, a Cray system at Los Alamos National Laboratory, ranked sixth; Titan, a Cray system at Oak Ridge, ranked ninth; and Sequoia, an IBM system at Lawrence Livermore, ranked tenth.

Summit, which is devoted to open science, had achieved the number one ranking on the last TOP500 list published in June, while Sierra, focused on national security applications, was then in the number three spot. At that time the two newly deployed systems were still in the process of commissioning and consequently running at less than full capability.

Today’s rankings better reflect their capabilities as fully commissioned systems. Both systems saw significant improvement in their score on the Linpack Benchmark that is used to determine the TOP500 ranking, with Summit rising from 122.3 petaflops (PF) in June to 143.5 PF currently, and Sierra rising from 71.6 PF to 94.6 PF. The next ranked system is China’s TiahuLight, with a Linpack score of 93.0 PF.

A second Chinese system, as well as Swiss, Japanese, and German systems round out the top ten list.