China whizzes past US to cement top spot in supercomputer race

China has overtaken the US to have the most supercomputers in the list of the world's fastest 500 systems.

China has for years claimed the top spot on a list of the 500 fastest supercomputers. Now it has topped the overall numbers chart as well.

The communist nation accounted for 202 of the globe's highest performance machines, according to the latest Top500 survey.

By contrast, the US had 143 supercomputers. That marks its lowest level since the bi-annual study began, 25 years ago, but still it secured second place. Japan placed third with 35 systems, and Germany fourth with 20.

In the previous survey, published in June, the US still had a lead of 169 supercomputers to China's 160.

The reversal of fortunes reflects China's increased investment in research and development - according to a recent study, the country now accounts for about 20 per cent of the world's total R&D expenditure.

The news underscores the relentless ascent of China's supercomputing trajectory in recent years. It also marks a notable shift in the international balance of high-end computing power that's closely tied to industrial, academic and military abilities.

Supercomputers are typically large, expensive systems that can occupy entire buildings and feature tens of thousands of processors designed to carry out specialised calculation-intensive tasks.

Examples include climate change studies; nuclear weapons simulations; oil prospecting; weather forecasting; DNA sequencing; and modelling biomolecules.

Performance is measured in petaflops (one thousand trillion floating point operations per second). A flop can be thought of as a step in a calculation.

China's fastest computer - the Sunway TaihuLight - maintained its lead as the world's speediest, performing at 93 petaflops. By contrast, the US's fastest - Titan - ranks fifth in the world, with a maximum performance of 17.6 petaflops.

The top two machines both are in China. Sunway TaihuLight, at China's National Supercomputing Center in Wuxi, is followed by Tianhe-2 at the National Supercomputer Center in Guangzho, the No 2 machine which scored 33.86 petaflops. They've held the top two spots for two years.

The United States might reclaim the top spot on the Top500 list, though. An IBM-built machine called Summit at Oak Ridge National Laboratory is designed to reach about 200 petaflops, double the performance of Sunway TaihuLight. It's in a 10,000-square-foot facility that's got a 20-megawatt power system for running the machine and keeping it cool. That's enough electricity to power about 16,300 houses.

For years, supercomputing speeds increased steadily with each new release of the Top500 list. In about 2012, though, progress improvements slowed down a notch, limited by diminishing processor speed improvements.

The Top500 organisers also have begun ranking supercomputers by a newer speed test designed to better reflect the range of computing tasks the machines handle, the High-Performance Conjugate Gradient (HPCG) benchmark.

By this measure, Fujitsu's K Computer at the RIKEN Advanced Institute for Computational Science in Japan is the top performer.The list's authors said the latest figures also indicated China had overtaken the United States in terms of aggregate performance, accounting for 35.4 per cent of the list's total processing power versus the US's 29.6 per cent.

At the SC 17 supercomputing show that started Monday in Denver, US space agency NASA will show off supercomputing work into precise simulations of climate change on earth, the aerodynamics of drones that fly using multiple propellers and detailed forecasts of shock-wave damage from meteors.

HP Enterprise is the top maker of supercomputers in late 2017, as measured by the number of machines on the Top500 list of the world's most powerful systems.

The Top500 list, released twice a year in conjunction with the annual SC conference, is compiled by researchers at Lawrence Berkeley National Laboratory, the University of Tennessee and cloud-computing company Prometeus. It ranks supercomputers by how fast they can perform mathematical calculations on an imperfect but still useful speed test called Linpack. Results are measured in Flops.

Erich Strohmaier, one of the survey's co-founders, told the BBC that many of the Chinese systems had been created to earn money, with the owners renting out their processing power to local and international firms.

"At the very high end - the systems in the top 10 - those are there for two reasons," he added. "One is simply the prestige attached with [being in the lead] in a market that used to be a prime example of US technology dominance. The other is to do with scientific exploration and national security - a lot of these systems are used for calculations related to weapons systems."