China's Tianhe-1 has overtaken Nebulae to regain top spot as China's fastest computer according to a new list of China's Top 100 supercomputers released Thursday.

On the biannual world TOP 500 list published in June, China's Nebulae machine took the second spot only after the U.S.'s Jaguar system, while Tianhe-1 took seventh place.

Housed at the National Center for Supercomputing in northern port city of Tianjin, Tianhe-1, meaning Milky Way, has a sustained computing speed of 2,507 trillion calculations, or 2.507 petaflops, per second.

It has a theoretical speed of 4.7 petaflops per second, according to a R&D research member of Tianhe-1. A petaflop is equivalent to 1,000 trillion calculations.

Nebulae housed in Shenzhen is capable of sustained computing of 1.271 petaflop per second (PFlop/s) on the Linpack benchmark, a measure for ranking supercomputers in world Top 500 list.

The U.S. leads the world in supercomputing and is home to more than half of the top 500 supercomputers. The Jaguar system at Oak Ridge National Laboratory in Tennessee has a speed of 1.75 PFlop/s.

The enhanced Tianhe-1 has upgraded Intel CPUs, NVIDIA GPUs, and new domestically developed FeiTeng-1000 CPUs have been installed, the developer the National University of Defense Technology (NUDT) said.

Tianhe-1 has begun trial use among target clients including Tianjin Meteorological Bureau and the National Offshore Oil Corporation data center. "It can also serve the animation industry and bio-medical research," said Liu Guangming, director of the National Center for Supercomputing in Tianjin.

In September 2009, the NUDT created Tianhe-1 with a sustained computing speed of 0.5631 PFlop/s, the fastest supercomputer in China at that time.

The new technical data of Tianhe-1 has been submitted to the world Top 500 list and the next list will be released in November.

(Xinhua News Agency October 28, 2010)