The Department of Energy has signed a $97 million contract with Cray Inc. and Nvidia to build the world's fastest supercomputer. The new machine, named Titan, will replace the existing Jaguar supercomputer at the Oak Ridge North Laboratory, upgrading it with AMD Opteron Interlagos processors and Nvidia Tesla 20-series GPUs. The machine combines the AMD processors and Nvidia GPUs on the same node, allowing for more efficient calculations, and aims to achieve of peak speeds between 10 and 20 petaflops, which would allow it to claim the top spot from a 8-petaflop Japanese system. The first phase of the upgrades is expected to be completed by the end of the year, with the second phase scheduled for the second half of 2012. Of course, it may not even be the fastest supercomputer by then — a few years ago, IBM announced a 20-petaflop system that's scheduled for delivery in 2011.