Chinese websites are claiming the country has overtaken the US as the home of the world’s fastest supercomputer. The official result is scheduled to be announced next week.

The rankings in question are the TOP500 project, which has published a list twice a year since 1993. It measures the maximum speed achieved in a standard test, with tiebreaks decided by the theoretical peak.

The current number one ranked machine is named Jaguar, a Cray XT5 system housed at the Oak Ridge National Laboratory in 2009. It’s been in the top spot for a year and achieved that position with a speed of 1.759 petaflops (1,759 trillion calculations per second.)

But now reports from China claim a machine named Tianhe-1 (which means Milky Way) is number one in that country. It’s said to have achieved a sustained processing speed of 2.507 petaflops, blowing away Jaguar. While the next TOP-500 rankings period doesn’t close until Sunday it appears that, if the figures are correct and verified, there’s virtually no chance of a rival machine beating the achievement.

In the last rankings, released in May, Tianhe-1 was “only” listed as achieving 563.1 petaflops, and even its theoretical maximum was only half the speed it’s now said to have achieved.

This would be the first time since 2004 that the US has not held the top spot: Jaguar was preceded as number one by IBM’s Roadrunner and Blue Gene/L. Japan is the only other country to produce machines topping the list. If there is some consolation for the US, the staggering improvement in Tianhe-1 looks to be partly the result of an upgrade involving Intel and NVIDIA chips.

The apparent takeover of the number one slot by China won’t come as a major surprise. Last year the Chinese-made Nebulae debuted in second place, and its theoretical maximum speed was the highest on the list.

As is common with supercomputers, Tianhe-1’s uses include meteorological simulation, a task that is simple in concept but involves numerous calculations to deal with the vast range of variable outcomes.

(Picture credit: Tianhe-1 via National University of Defense Technology)