Always strive to learn something useful. --Sophocles

Supercomputers are now at the petaflop speed point, the current fastest is a Chinese rig that does 2.57. DARPA asked a study group what it would take to build an exaflop computer, and the basic answer is that it isn't really possible right now. Power requirements, excluding cooling for the rig, would require a nuke plant next door...

http://spectrum.ieee.org/computing/hardware/nextgeneration-supercomputers/0