The computing cluster, located at the US Department of Energy's Livermore California labs, retained the top spot on the Top 500 supercomputer list despite challenges from several new systems.
Second on the list was the Cray XT5 cluster at Oak Ridge Laboratory in Tennessee. This is the second time that the Oak Ridge system has been in the number 2 slot on the list.
While the top two spots were unchanged from the previous ranking in November of 2008, several new systems appeared within the top 25 spots on the list, adding new facilities and locations to the top supercomputing ranks.
Debuting on the list in the third spot was the new IBM BlueGene cluster installed at the Forschungszentrum Juelich (FZJ) facility in Germany. The system is one of two at the FZJ facility to enter the top ten and is one of three supercomputer systems to debut in the top ten this year.
Also making a debut in the top 15 spots was the new supercomputing system from the King Abdullah University of Science and Technology in Saudi Arabia. The supercomputing cluster came in 14th overall and is the fastest system outside of the US and Germany.
The two fastest systems in the UK claimed the 25 and 26 slots. Both are IBM Power 575 clusters located at the European Centre for Medium-Range Weather Forecasts in Reading.