World’s most powerful supercomputer at present is __:

Titan
A computer called Titan, which is 10 times more powerful than the last lab machine, has claimed the title of the world’s most powerful supercomputer. Titan uses microchips more usually used for video-gaming to crunch numbers for climate studies, models of advanced materials and alternatives to petrol. The machine has seized the top spot in the Top500 – a closely-watched global league of the fastest supercomputers. Built by Cray at the US government’s Oak Ridge National Laboratory in Tennessee, Titan is 10 times more powerful than the lab’s last supercomputer, Jaguar, which led the world as recently as 2009. Titan was measured at 17.59 petaflops or 17.59 thousand trillion calculations per second beating the previous record of 16.32 petaflops, held by Sequoia, a supercomputer at Lawrence Livermore National Laboratory in California, which simulates nuclear attacks.