U.S. researchers are bracing for the prospect that China will once again have the world's fastest computer—and could hang on to the speed crown for some time.

China's National University of Defense Technology last week informed visiting scientists about a massive machine in Changsha whose initial test results appear likely to top the next ranking of the 500 largest supercomputers, scheduled for release later this month.

Such systems, used heavily by government agencies for purposes such as weapons design and intelligence-gathering, have long been seen a symbol of national competitiveness—and the focus of recent leapfrogging moves by the U.S., China and Japan.

A supercomputer in China unveiled in 2010 briefly topped the global speed ranking. But U.S. research institutions recently have fielded the fastest hardware, led by a machine called Titan at Oak Ridge National Laboratory.

The new Chinese system—called the Tianhe-2, or Milkyway-2—uses two different kinds of computer chips from Intel Corp. as well as some homegrown circuitry, according to Jack Dongarra, a U.S. supercomputer expert who saw the system last week. He published details about the machine that were reported earlier by the publication HPCwire.