Maybe China Doesn't Have the World's Best Computer

We reported last week that a Chinese supercomputer, the Tianhe 1A, had officially become the world's fastest, according to a standard testing methodology. Now, the ever-perspicacious Chris Mims at Technology Review is questioning whether the Tianhe 1A can actually match the real-world performance of the best computers from other countries.

What's in a number? If you're the engineers behind China's Tianhe 1A, the number 4.7 means a lot -- it's the number of petaflops (as in floating point operations per second) that the "world's fastest" supercomputer can chew through at its peak performance.

The key word here is "peak performance": while the Linpack benchmark used to officially determine the speed of the world's fastest supercomputers measures their ability to do calculations in short bursts, in the real world of scientific computing, what often matters most is a machine's ability to sustain that performance.

In other words, the Tianhe 1A comes on strong, but American supercomputers can last all night - or sometimes many days, depending on the scale of the problem they're tackling. "It's very difficult to achieve anywhere near peak performance on GPUs," says Thom Dunning, director of the National Center for Supercomputing Applications.

GPUs are the NVIDIA-built graphics processing units that comprise the bulk of the computing power in the Tianhe 1A supercomputer, which also includes traditional CPUs in its hybrid design.

Read the full story at Mims's Bits at Technology Review.