"It looks like Los Alamos, and IBM may have reached a petaflop with Roadrunner," he said.

Roadrunner was built for Los Alamos National Laboratory by IBM, using 6,912 dual-core Opteron processors from Advanced Micro Devices (AMD) and 12,960 of IBM's Cell eDP accelerators. Early indications are that the machine's Cell processors have reached a score of 1.33 petaflops, as measured by the Linpack benchmark, while the Opterons reached 49.8 teraflops, Stevens said.

With the petascale barrier seemingly broken, researchers are starting to ask what's needed to build an exascale system, one capable of a billion billion calculations per second, or a thousand times faster even than Roadrunner.

Extrapolating from the increases in cores per node, the number of nodes, and the power consumption of supercomputers over recent years, Stevens predicts that by 2019, we could have supercomputers capable of 1.2 exaflops, and containing 400,000 nodes with 128 processor cores each -- and consuming a staggering 80MW.

By that stage, though, competition between Europe, Japan and the US for the supercomputing crown may no longer be an option.

"We may have to cooperate at a global level to push past one petaflop," said Stevens.