The Green500 might not be quite as well known as the Top500, but it's no less of an honor to be counted among the world's most energy efficient supercomputers. NVIDIA is tooting its own horn for making it on to the list for the second year in a row as part of the "greenest" petaflop machine. The Tsubame 2.0 at the Tokyo Institute of Technology's Global Scientific Information Center is powered by Intel's Xeon CPUs, but N
