IBM’s Roadrunner, a 1.105 petaflop/s supercomputer at Los Alamos National Laboratory, retained the top spot as the world’s fastest supercomputer in the 32nd edition of the list of the world’s TOP500 supercomputers, released Friday.

A close second place went to the Cray XT5 supercomputer at Oak Ridge National Laboratory, called Jaguar. The system, only the second to break the petaflop/s barrier, posted a top performance of 1.059 petaflop/s in running the Linpack benchmark application.

The No. 3 system, Pleiades, is a new SGI Altix ICE system installed at NASA Ames, with 487 teraflop/s.

One petaflop/s represents one quadrillion floating point operations per second.

Nine of the top 10 supercomputers are located in the United States. The most powerful system outside the U.S. is the Chinese-built Dawning 5000A at the Shanghai Supercomputer Center, with 180 teraflops/s.