Anonymous Coward writes "The most powerful supercomputer available for general scientific research in the United States has undergone an upgrade that's doubled its peak performance. The Cray XT3 supercomputer at Tennessee's Oak Ridge National Laboratory can now perform up to 54 trillion calculations per second, up from its previous peak of 25 trillion calculations. 'It is probably the fifth-fastest machine' in the world, said Thomas Zacharia, associate laboratory director. 'It is clearly the fastest open-science machine in the U.S. today.'"