The U.S. is back at the top of the global supercomputer list.

You can thank IBM’s BlueGene for the honor.

For the first time since 2009, a U.S. supercomputer is the world’s fastest. according to the TOP 500 list, which follows the big computing business. The TOP 500’s latest ranking came out Monday. it is released twice a year.

The IBM BlueGene runs at the Department of Energy’s Livermore lab.

Named Sequoia, the BlueGene/Q  system runs 1.573 million cores with a speed of 16.32 petaflops.

(Flop/s stand for floating-point operations per second; peta is 10 to the 15th power, says Wikipedia. A petaflop is the ability of a computer to do one quadrillion floating point operations per second, says Webopedia.)

A Fujitsu K Computer in Japan ranks second at 10.51 petaflops. It had ranked No. 1 on the previous two lists and was the first to crack the 10 petaflop barrier.

Meanwhile, a new IBM machine called Mira debuts at No. 3, running 8.15 petaflops. It’s absed at the Argonne National Laboratory in Illinois.

Intel processors still dominate the TOP 500 with 74.4 percent of the 372 ranked systems, However, that’s down nearly 8 percent from the previous list.

AMD is second at 12.6 percent share.

IBM is third at 11.6 percent, increasing to 58 systems from 49.

IBM employs some 10,000 people across North Carolina.

[IBM ARCHIVE: Check out a decade of IBM stories as reported in WRAL Tech Wire.]