With an impressive new record of 16.32 Petaflops, the Lawrence Livermore Sequoia supercomputer has returned the U.S. to the top spot of the Top500 list for the first time since November 2009. The June 2012 Top500 list was announced at the 2012 International Supercomputing Conference (ISC) underway this week in Hamburg, Germany.

IBM and DOE Take #1 and #3

Sequoia is an IBM BlueGene/Q system installed at the Department of Energy’s Lawrence Livermore National Laboratory and debuted on the Top500 last November at number 17. Joining Sequoia on the list at number 3 is Mira, a 8.15 Petaflop DOE IBM BlueGene/Q supercomputer, installed at Argonne National Laboratory.

Both systems are powered by Power BQG 16-core 1.6 GHz processors, Sequoia using 1,572,864 cores and Mira 786,432. IBM unveiled these two systems in August 2011, noting performance and efficiency gains over its Power-7 architecture that would have been used in the derailed Blue Waters project. Both systems run Linux and have a custom interconnect. Sequoia and Mira are also two of the most energy efficient systems on the list, with Sequoia using 7,890 kilowatts and Mira using 3,422 kilowatts.

Holding the top spot for the last two lists, Japan's K Computer remained at 10.51 Petaflops and took the number 2 position. China's Tianhe-1 fell to number 5.

Europe back in force

Leading a strong representation from Europe in the top ten was Germany's SuperMUC, an IBM iDataplex system installed at Leibniz Rechenzentrum. Another German machine, the JuQUEEN BlueGene/Q at Forschungszentrum Juelich, is number 8. Italy makes a debut in the top 10 at number 7 with another IBM BlueGene/Q and France occupies number 9 with a homegrown Bull supercomputer.

With a considerable increase from the stagnant November 2011 list, the total performance of all systems on the list increased 49.2 Petaflops to a total of 123.4 Petaflops. The number 500 machine on the list notched a performance level of 60.8 Teraflops, which was enough to reach number 332 just seven months ago. IBM kept its lead vendor status with 213 systems, and the share of IBM Power processors increased from 49 to 58 systems. Use of co-processors in systems was up 19 from the November 2011 list, with NVIDIA powering 53 of the 58 installations.

Top500 list conversations and ISC conference events can be followed on Twitter hashtags TOP500 and ISC12.