Fujitsu's K computer, the only supercomputer in Japan that made the top 10, is an incredibly powerful machine. It reigned as the fastest supercomputer in the world on both 2011 lists and now sits at No. 2 with a huge gulf in performance over IBM's new Mira. It can perform at up to 11 petaflops.
The K Computer is located at Japan's RIKEN Advanced Institute for Computational Science, where it performs scientific operations including global disaster prevention, meteorology and medical research [source: Fujitsu]. Unlike many of the other supercomputers on the list, it doesn't run on IBM architecture. The K computer uses Fujitsu's own SPARC64 VIIIfx octo-core processors. Seven hundred and five thousand computer cores help it churn through operations at an incredible pace.
But believe it or not, the fastest supercomputer in the world is leaps and bounds more powerful than the K computer.