Thomas Edison lost the war when it came to his advocacy of direct current as the best way to distribute electricity. But his ideas are now winning battles as a solution to growing power and cooling problems in the data center. DC advocates say that plugging servers into AC power is inefficient, and switching to DC cuts down on waste heat and component failure. The University of Florida has even bought 200 DC servers.

Proponents argue that using DC outside the server removes some of the inefficiencies of power supplies that convert AC electricity to DC. Servers without such power supplies don't have to contend with as much waste heat and attendant component failure.

"It keeps the units considerably cooler within the chassis themselves and saves us somewhere between 10 and 20 percent over the AC-powered alternative," in terms of electrical costs, said Charles Taylor, a senior systems engineer at the University of Florida. Taylor installed an $840,000 cluster of 200 Rackable servers as a mini-supercomputer at the university in October.