For those of you who like your supercomputers fast AND green, the latest list of the most energy-efficient ones in the world has just been published. The ranking is a twist on the well-known Top 500 supercomputers list; the green slice on this list ranked using the measure of FLOPs per watt.
The greenest system listed is a QPACE system that uses the IBM PowerXCell 8i processor. There are actually three tied for the greenest-fastest performance. They are housed at the Julich Supercomputing Centre, University of Regensburg and the University of Wuppertalare. All three produce 773 millions of floating point operations per second (Mflops) per watt.
IBM is also behind the list's most energy-efficient x86-only cluster. The cluster, ranked 9th, is housed at Mississippi State University.
IBM actually dominates the Top 20 of this energy-efficiency, claiming 17 of the top 20 positions. The exceptions include three systems from China: the Nebulae at the National Supercomputing Centre in Shenzhen, China, (which shows up as No. 4); the Mole-8.5 Cluster Xeon system at the Institute of Process Engineering, Chinese Academy of Sciences (No. 8) and Tianhe-1(TH-1) at the National SuperComputer Center in Tianjin/NUDT.
IBM used the list's publication to publicize the fact that its Aquasar, a hot-water-cooled supercomputer design, is now live in a deployment at the Swiss Federal Institute of Technology in Zurich, Switzerland. The technology produces about 450 Mflops per watt. It makes innovative use of the system's waste heat.
This video explains on how the technology works: