The world's most prestigious supercomputers are usually spotlighted in the Top500 list of the world's fastest systems.
But there is also a similarly interesting, albeit less known listing that is showing tremendous progress in the power efficiency of some supercomputers. Intel, AMD and Nvidia are the main proponents of this group.
ORNL's Titan may be the world's fastest supercomputer, but it is only the third most efficient, according to Green500. The honor of being the greenest supercomputer system goes to University of Tennessee and its Beacon system, which is based on Xeon E5-2670 and Xeon Phi 5110P processors. The computer delivers 2,499.44 Mflops per watt.
The ORNL Titan, which integrates AMD Opteron 6274 processors and Nvidia Tesla K20x graphics cards, posted 2,142.77 Mflops per watt.
The three systems cannot be compared in their absolute performance. Titan holds position #1 on the Top500 list; SANAM can be found at #52 and Beacon at #253.
Titan (560,640 CPU cores, 46,6 million Nvidia CUDA processors) delivers a sustained performance of 17.6 Pflops, while SANAM (38,400 CPU cores, 1.5 million AMD stream processors) is rated at 421 TFlops, and Beacon at 110.5 TFlops (9,216 CPU cores, undisclosed number of Xeon Phi 5110P cards with 60 cores each).