June 18, 2008 - IBM's Roadrunner has taken home top ranking on the Top500 bi-annual list of the world's most powerful supercomputers.

The system, built for the U.S. Department of Energy’s Los Alamos National Laboratory, is the first to achieve a peak performance of more than 1 petaflop (one quadrillion floating point operations per second).

Roadrunner is also one of the most energy efficient systems on the list. Compared to most traditional supercomputer designs, Roadrunner’s hybrid format - which runs on a combination of microprocessors and a cell engine originally designed for video game platforms - "sips" power (2.35 megawatts) and delivers a record-breaking 437 million calculations per watt, according to IBM.

IBM says it expects Roadrunner to place among the top energy-efficient systems later this month when the Green500 ranking of energy-efficiency supercomputers is issued. The first-ever Green500 list was released last November.

Find the complete Top500 rankings here.