In June 2011, a Japanese supercomputer capable of performing 8.16 quadrillion calculations per second (petaflop/s) became the new number one system, putting Japan back in the top spot for the first time since the Earth Simulator was dethroned in November 2004. The system, called the K computer, is at the RIKEN Advanced Institute for Computational Science (AICS) in Kobe. The K computer is named for the Japanese word "kei", which stands for 10 quadrillion.
The K computer, built by Fujitsu, originally combined 68,544 SPARC64 VIIIfx CPUs, each with eight cores, for a total of 548,352 cores—almost twice as many as any other system at the time. The K computer was also more powerful than the next five systems on the list combined.
In November 2011, the K computer retained the No. 1 position and became the first computer to top 10 petaflop/s after a full build-out using 705,024 SPARC64 processing cores. The upgraded system achieved an impressive 10.51 petaflop/s on the Linpack benchmark. The K computer was also one of the most energy-efficient systems on the list.
|1||Titan - Cray XK7 , Opteron 6274 16C 2.200GHz, Cray Gemini interconnect, NVIDIA K20x|
|2||Sequoia - BlueGene/Q, Power BQC 16C 1.60 GHz, Custom|
|3||K computer, SPARC64 VIIIfx 2.0GHz, Tofu interconnect|
|4||Mira - BlueGene/Q, Power BQC 16C 1.60GHz, Custom|
|5||JUQUEEN - BlueGene/Q, Power BQC 16C 1.600GHz, Custom Interconnect|
|6||SuperMUC - iDataPlex DX360M4, Xeon E5-2680 8C 2.70GHz, Infiniband FDR|
|7||Stampede - PowerEdge C8220, Xeon E5-2680 8C 2.700GHz, Infiniband FDR, Intel Xeon Phi|
|8||Tianhe-1A - NUDT YH MPP, Xeon X5670 6C 2.93 GHz, NVIDIA 2050|
|9||Fermi - BlueGene/Q, Power BQC 16C 1.60GHz, Custom|
|10||DARPA Trial Subset - Power 775, POWER7 8C 3.836GHz, Custom Interconnect|