China may have already crossed the exascale barrier - twice.

The country is secretly operating the two most powerful supercomputers in the world, and is the first nation to run systems capable of more than one exaflops (10¹⁸ floating-point operations per second), The Next Platform reports.

Officially, the title of the world's most powerful supercomputer is currently held by Japan's Fugaku supercomputer, capable of 442 petaflops.

Citing an anonymous source, TNP claim that The National Supercomputing Center in Wuxi is home to the Sunway “Oceanlite” supercomputer.

This system is a successor to the Sunway TaihuLight, officially China's most powerful supercomputer. In March, China tested Oceanlite to the Linpack benchmark and it hit 1.3 exaflops peak performance with 1.05 sustained performance, with a 35MW power consumption.

The new supercomputer is being used, among other things, for quantum simulation, with new research expected to be announced soon. It is thought to feature 42 million cores of Chinese chips.

At the same time, China has another supercomputer at the National University of Defense Technology (NUDT) capable of around the same performance, although its power consumption is not known.

The Tianhe-3 supercomputer is based on Phytium's FeiTeng chips, which were developed after US trade sanctions stopped China from acquiring Intel Xeon Phi processors.

The new system was also benchmarked in March. The following month, Phytium and Sunway were added to a list of Chinese companies sanctioned by the US government. Phytium was cut off from chip manufacturer TSMC.

It is not known why China has not publicly disclosed the two supercomputers, with major systems traditionally ranked twice a year by Top500.

The US is soon set to launch its own exascale system - one that it has called the first exascale supercomputer in the world. At 1.5 exaflops (likely 1.3 sustained performance), Frontier will become the new world's most powerful supercomputer. Work is currently underway installing the 29MW system. It will soon be joined in the US by the oft-delayed 1 exaflops Aurora supercomputer, and in 2023 by the 2 exaflops El Capitan system.

All these systems could pale into insignificance when compared to an even more ambitious project TNP's source disclosed - China's 'Futures' program, which hopes to develop a 20 exaflops system by 2025.