China is putting the U.S. firmly in the shade in the battle for supercomputer supremacy.

For the first time ever, China has taken the lead in the number of supercomputers on a closely watched list of the 500 fastest systems on the planet. It has 167, overtaking the U.S. at 165, according to the researchers who compile the ranking.

China has also strengthened its grip on the top of the list, with its machines taking both first and second place. And the new supercomputer that has leaped in at No. 1 -- known as Sunway TaihuLight -- is built completely on homegrown processors rather than drawing on U.S. chip technology.

The top spot had previously been held since 2013 by China's Tianhe-2, which was based on Intel (INTC) processors.

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Supercomputers are typically used for predicting scenarios because of their incredible power to crunch numbers. They can create precise models of complex environments, such as predicting weather patterns, mapping DNA or simulating nuclear explosions.

That also makes them a sensitive potential tool for national security.

Last year, the U.S. government blocked Intel and Nvidia (NVDA) from selling new chips for upgrades at four supercomputer centers linked to Tianhe-2 because it said it believed they were "used in nuclear explosive activities." Chinese officials have denied the allegations.

Sunway, which is made out of homegrown tech, doesn't have to worry about such issues. And it's really freaking powerful, running twice as fast as Tianhe-2.

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The top ranked U.S. system, Titan, came in third place, but it lags China's top dog by a long way. Sunway is more than five times as fast.

The researchers who put together the Top 500 list twice a year attributed China's growing dominance to "a surge in industrial and research installations registered over the last few years."

The U.S. is trying to claw back lost ground. Last summer, President Barack Obama signed an executive order to announce the National Strategic Computing Initiative, which will be responsible for building the world's fastest supercomputer.

But it's going to take some time before it produces anything to give Sunway a run for its money.