Today’s best process technology requires about 70 picojoules per floating point operation (FLOP). A US Defense Advanced Research Agency (DARPA) study projected that by the end of the decade, this will drop to 5-10 picojoules per FLOP. Doing the math, a 2020 Exascale system would require 5-10 megawatts to perform 1 ExaFLOP of calculations. While that is a lot of power, there are certainly many data centers today that can support 5-10 metawatts. So why all the concern about energy efficiency? Unfortunately, FLOPs alone are not the power driver in modern supercomputers. The energy cost of moving two 64 bit operands in and out of the processor is estimated at 1000 to 3000 picojoules per FLOP, and that means up to 1 gigawatt would be required for an Exascale system, well outside the capabilities of even the world’s largest data centers.
Read the Full Story.