November 22, 2010 | China may have taken top honors in the most recent Top500 listing, but IBM walked away with another award: the world's most energy-efficient supercomputer. The Green500 list was announced on Friday at Supercomputing 2010 in New Orleans. BlueGene/Q is 165 % more efficient than the Chinese supercomputer and 77 % more power-efficient than the Tokyo Institute of Technology's Tsubame 2.0, the second best machine on the Green500 list. PC World