The inaugural Green500 list was announced on November 15, 2007 at SC|07. As a complement to the TOP500, the unveiling of the Green500 ushered in a new era where supercomputers can be compared by performance-per-watt.
While the selection of any power-performance metric will be controversial, we currently opt for "FLOPS-per-Watt" given that it has already become a widely used metric in the community and for reasons outlined in, Making a Case for a Green500 List, which was presented at the 2nd IEEE IPDPS Workshop on High-Performance, Power-Aware Computing, April 2006.
At SC|09, the Green500 announced the creation of three new exploratory lists -- Little, Open, and HPCC -- as companions to the Green500 list. While the Green500 list continues to be the official rankings, these new lists allow us to explore new metrics based on community input.
The Green500 List
The Green500 list, ranks the top 500 supercomputers in the world by energy efficiency. The focus of performance-at-any-cost computer operations has led to the emergence of supercomputers that consume vast amounts of electrical power and produce so much heat that large cooling facilities must be constructed to ensure proper performance. To address this trend, the Green500 list puts a premium on energy-efficient performance for sustainable supercomputing.