It seems there’s a new supercomputer every month, but now there’s a new standard for differentiating them – by how green they are. The Grape DR, a Japanese cluster at the University of Tokyo, has just been named the world’s greenest supercomputer, topping out over a German supercomputer according to the Little Green500 list. The Green500 is the organization that keeps track of how energy efficient all the supercomputers are by measuring computing power against power consumption. Clearly the tidiness of the wiring is not part of the ranking criteria.
The Green500 ranks computers according to their speed versus their power consumption, which is measured as an efficiency ratio. Since the fastest computers are accelerator-based computers, their efficiency is defined as ‘millions of floating-point operations per second’ (MFLOPS) divided by ‘watts’ (W) or MFLOPS/W. University of Tokyo’s Grape-DR computer has an efficiency of 815.43 MFLOPS/W, which just beat out Forschungszentrum Juelich’s computer, which has an efficiency of 773.38 MFLOPS/W.
There are two main lists managed by Green500 – the Green500 and the Little Green500, with the difference being that the Little list is designed to help guide purchasing decisions for smaller institutions. To be eligible for the Little list, a supercomputer must be as “fast” as the 500th ranked supercomputer on the TOP500 list 18-months prior to the release of the Little Green500. The Grape-DR, which is powered by a combination of 128 Intel Core i7-920 processors and four bespoke accelerator chips, is at the top of the Little Green500 and Forschungszentrum Juelich’s IBM-based computer is at the top of the Green500 list.