We all know that the concept of green computer can be twisted to serve pretty much any side of the argument (I wrote just a few days ago why the mainframe might NOT be considered green) but the fact is there are a lot truly BIG computers out there, in the sense that they need to crunch gazillions of computations in any given work day. So I always like following what company is on top of the Supercomputing Green500 List that is compiled on a regular basis by Green500.org.
The existence of the list is a not-so-subtle push on the part of this organization to encourage the development of technologies that marry energy efficiency and performance.
Systems built with IBM technology claimed 18 of the top spots on the latest list, including the No. 1 position. That honor went to the IBM BladeCenter QS22 that is used at the Interdisciplinary Centre for Mathematical and Computational Modeling, University of Warsaw. The systems generate more than 536 millions of floating point operations per second for every watt of energy that it uses. The fastest computer on this list, the IBM supercomputer used by the Los Alamos Laboratories, is fourth on the ranking.