China has the world's fastest supercomputer, the Tianhe-1A supercomputer, which is capable of carrying out more than 2.5 thousand trillion calculations a second.
(The computer has more than 7,000 graphics processors and 14,000 Intel chips and has taken over the top spot from America's XT5 Jaguar at the Oak Ridge National Laboratory (ORNL) in Tennessee, which can only carry out 1.75 petaflops. One petaflop is the equivalent of 1,000 trillion calculations per second. I still love the word "petaflop". It reminds me of Sam.)