In what has become a closely watched event in the world of high-performance computing, the 25th edition of the TOP500 list of the world’s fastest supercomputers was released today (June 22, 2005) at the 20th International Supercomputing Conference (ISC2005) in Heidelberg Germany. The new TOP500 list, as well as the previous 24 lists, can be found on the Web at its Web site. The No. 1 position was again claimed by the BlueGene/L System, a joint development of IBM and DOE’s National Nuclear Security Administration (NNSA) and installed at DOE’s Lawrence Livermore National Laboratory in Livermore, Calif. BlueGene/L also occupied the No. 1 position on the last TOP500 list issued in November 2004. However, the system was doubled in size during the last six months and reached a new record Linpack benchmark performance of 136.8 TFlop/s (“teraflops” or trillions of calculations per second). This system, once completed, will again be doubled in size and is expected to remain the #1 Supercomputer in the world for the next few editions of the TOP500 list. The pace of innovation and performance improvements seen at the very high end of scientific computing shows no sign of slowing down. This time, half of the TOP10 systems on the November 2004 TOP500 list were displaced by newly installed systems and the last 201 systems on the list from last November are now too small to be listed any longer. The new #2 listed system is also an IBM Blue Gene system with the same architecture but smaller in size than the #1 BlueGene/L at LLNL. It was recently installed at IBM’s Thomas J.Watson Research Center in Yorktown, N.Y. and reached 91.2 TFlop/s. It is closely followed by the Columbia system built by SGI and installed at the NASA Ames Research Center in Mountain View. Calif. Columbia clocked in at 51.87 TFlop/s. The NEC-built Earth Simulator, which has a Linpack benchmark performance of 35.86 TFlop/s and had held the No. 1 position for five consecutive TOP500 lists before being replaced by BlueGene/L last November, is now shown as No. 4. After a close race to the finish line, the updated the IBM-built MareNostrum cluster installed at the Barcelona Supercomputer Center in Spain, gained the No. 5 spot with 27.91 TFlop/s, just barely ahead of the second European system on the list, an IBM Blue Gene system owned by ASTRON and installed at the University of Groningen in the Netherlands, listed with 27.45 TFlop/s. The #10 spot was captured by an early measurement of Cray’s new Red Storm System at Sandia National Laboratories with 15.25 Tflops/. This is also the new entry level for the TOP10 up from just under 10 TFlop/s Linpack performance six months ago. IBM continues to establish itself as the dominant vendor of supercomputers with now more than half of the list (51.8 percent) carrying its label. The Blue Gene architecture helped IBM to gain a similar standing at the very top of the list, where now six of the TOP10 systems are from IBM, five of these being Blue Gene systems. Here are some highlights from the newest Top 500: As predicted several years ago by the research team behind the TOP500 listing, only systems exceeding the 1 TFlop/s mark on the Linpack were qualified to enter the list this time. The system in No. 500 spot reached 1.166 TFlop/s. The entry level for the TOP10 exceeds 15 TFlop/s and the entry point for the top 100 moved from 2.026 TFlop/s to 3.412 TFlop/s. Entry level for the TOP500 is now 1.166 TFlop/s, compared to 850.6 GFlop/s six months ago. The last system on the list would have been listed at position 299 in the last TOP500 just six months ago. This exemplifies the continuous rapid turnover of the TOP500. The last system (#500) in June 2005 has about the same compute power as ALL 500 systems combined, when the list was first created 13 years ago in June1993. Total combined performance of all 500 systems on the list is now 1.69 PFlop/s (“petaflops” or thousand “teraflops”), compared to 1.127 PFlop/s six months ago. Other trends of interest: A total of 333 systems are now using Intel processors. Six months ago there were 320 Intel-based systems on the list and one year ago only 287. The second most-commonly used processors are the IBM Power processors (77 systems), ahead of Hewlett-Packard’s PA Risc processors (36) and AMD processors (25). There are 304 systems now labeled as clusters, making this the most common architecture in the TOP500. At present, IBM and Hewlett-Packard sell the bulk of systems at all performance levels of the TOP500. IBM remains the clear leader in the TOP500 list with 51.8 percent of systems and 57.9 percent of installed performance. HP is second with 26.2 percent of systems and 13.3 percent of performance and SGI is third with 5 percent of systems and 7.45 percent of performance. No other manufacturer is able to capture more than 5% in any category. The U.S is clearly the leading consumer of HPC systems with 294 of the 500 systems installed there (up from 267 six months ago). A new geographical trend, which started a few years ago, now emerges more clearly. The number of systems in Asian countries other than Japan is rising quite steadily. In this latest list, Japan is listed with 23 systems and all other Asian countries combined have an additional 58 systems. However Europe is still ahead of Asia, with 114 systems installed. China is home to 19 of the systems in Asia -- up from 17 systems six months ago. In Europe, Germany claimed the No. 1 spot from UK again, with 40 systems compared to 32. Six months ago, UK was in the lead with 42 compared to Germany’s 35 systems. The TOP500 list is compiled by Hans Meuer of the University of Mannheim, Germany; Erich Strohmaier and Horst Simon of NERSC/Lawrence Berkeley National Laboratory; and Jack Dongarra of the University of Tennessee, Knoxville.