We live in an ecologically minded era, where Ford spends more time talking up the new Mustang's mpg rating than its 0 - 60 times. Appropriate, then, that supercomputers are now being rated not on ultimate speed but on speed relative to power consumption. Top of the Green500 supercomputer list is the Grape-DR, a Japanese cluster at the University of Tokyo powered by a combination of 128 Intel Core i7-920 processors and four bespoke accelerator chips. That combination enables the system to manage 815.43 megaflops per watt, a good bit higher than the 773.38 rating an IBM
