Cray's XT5 supercomputer at Oak Ridge National Laboratory has claimed the "world's fastest supercomputer" crown from IBM's Roadrunner, according to the Top500 list announced at Supercomputer 2009 (Nov. 14-19, 2009, Portland, Ore.)

For the last three years, IBM's Roadrunner supercomputer has edged out Cray on the Top500 list, but this year Cray's XT5 finally beat Roadrunner with a 1.75 petaflop/second performance speed running the Linpack benchmark (compared to 1.1 petaflop for Roadrunner). The Top500 list reported that Jaguar has a theoretical peak capability to 2.3 petaflop/second.

IBM's Roadrunner was the first supercomputer to break the petaflop barrier in the summer of 2008. For the last two years, Cray's Jaguar was narrowly edged out by IBM's Roadrunner, but earlier this year Jaguar was upgraded at the Department of Energy's Oak Ridge Leadership Computing Facility. The upgrade, which was funded with $19.9 million from the U.S. Recovery Act, was intended to enable scientific simulations of climate change and for the development of new energy technologies.

Cray was founded in 1987 and for many years the name "Cray" was virtually synonymous with supercomputer. But with the advent of multicore architectures, Cray lost out to other manufacturers while it struggled to make a comeback. After 34 Top500 List awards, this is the first year that Cray has won the top prize.

Cray's Jaguar edged out IBM's Roadrunner with a whopping 69 percent faster execution of the standard Linpack performance benchmark by increasing the number of cores from 129,600 to 224,162, using 37,376 of AMD's newest six-core Istanbul processors, each with 2 Gbytes of memory.

In addition to Jaguar, another Cray XT5 at the National Institute for Computational Sciences, known as Kraken,  was ranked third on the Top500 list with a speed of 831.7 teraflops. Fourth was IBM's BlueGene/P system at the German Forschungszentrum Juelich (FZJ). Fifth was the Tianhe-1system installed at the National Super Computer Center in Tianjin, China. The Tianhe-1 is a hybrid design using both Intel Xeon central processors and AMD graphics accelerators--each node consists of two Intel Xeon CPUs and two AMD GPUs.

SGI counter-claimed at the Supercomputer 2009 conference that its Intel Nehalem-powered Altrix UV was the world's fastest supercomputer, but SGI uses a more modern benchmark than the old-school Linpack used by the Top500 to bestow the crown on Cray. SGI measured the performance of its Altrix UV with the Stream benchmark, which is optimized to measure the performance of shared memory supercomputers. SGI's Altix UV uses 2,048 Intel Nehalem-EX Xeon processors and has a scalable architecture that can accommodate up to 262,144 cores.