IBM Narrowly Maintains Top Supercomputer RankingIBM Narrowly Maintains Top Supercomputer Ranking

IBM's Roadrunner supercomputer barely held on to its ranking as the world's fastest computer, as Cray challenger Jaguar came close to snatching the crown from the defending champion at the Los Alamos National Laboratory.

The biannual Top500 list, released late Friday at the SC08 conference in Austin, Texas, showed Roadrunner reaching a speed of 1.105 petaflops per second, compared with Jaguar's 1.059 petaflops per second. The systems were the only two able to perform a quadrillion scientific calculations a second. Roadrunner reached the petaflop mark in June when it grabbed the crown.

Roadrunner is powered by nine-core PowerXCell processors, which are the same chips used in the Sony PlayStation 3, and runs the Linux operating system. Jaguar is powered by Opteron quad-core processors from Advanced Micro Devices and uses the CNL OS. Both systems are in national laboratories operated by the Department of Energy. Jaguar is located at the Oak Ridge National Laboratory.

Seven of the top 10 systems are located in Energy Department facilities, and nine of the top 10 are in the United States. The only top-10 system outside the United States is the Chinese-built Dawning 5000A at the Shanghai Supercomputer Center. The Dawning is the largest supercomputer operated with the Windows HPC 2008 OS.

Among vendors represented in the top 500, Hewlett-Packard led in the number of systems with 209, or 41.8%, taking the honor from IBM, which fell to No. 2 with 188 systems, or 37.6%. In June, IBM led with 210 systems, while HP was in second place with 183 systems.

A total of 379 systems, or nearly 76%, used Intel processors, about the same number as in June. IBM Power processors and AMD Opteron were nearly tied as the second-most-common processors with 60 and 59 systems, respectively. Graphics chipmaker Nvidia saw its technology being used in a top 500 system for the first time. The TSUBAME Grid Cluster at the Tokyo Institute of Technology also uses Intel Xeon and AMD Opteron chips and is built with NEC and Sun Microsystems hardware. Nvidia and rival AMD are making a big marketing and technology push to convince the scientific community and industry to use graphics processors in supercomputing.

Below the top two systems, speeds fell by more than half. The No. 3 supercomputer, a new SGI Altix ICE system called Pleiades, performed at 487 teraflops per second. The system is located at NASA Ames in Moffett Field, Calif.

Overall, the top 500 list shows that systems are getting faster. The last system on the current list would have been ranked 267 in June. Total combined performance of all the systems increased to 16.95 petaflops per second, compared with 11.7 petaflops per second in June and 6.97 petaflops per second a year ago.

The United States is the leading consumer of high-performance systems, with 291 of the 500 systems, up from 257 in June. Europe is second with 151 systems, down from 184 six months ago.

The Top500 list is compiled at the University of Mannheim, Germany; the Lawrence Berkeley National Laboratory; and the University of Tennessee, Knoxville. The full list is posted on the Top500 Web site.