IBM's Sequoia supercomputer has overtaken Fujitsu's K as the world's fastest, the first time an American company has claimed pole position since it was beaten by China two years ago.
Japanese brand Fujitsu's K Computer, a newly installed system, fell to second place. The top 10 list includes two supercomputers from China and Germany, and one each from France and Italy.
Two other supercomputers from the United States complete the list, the BBC reported.
IBM itself proved to be the leading manufacturer claiming five out of the top 10 spots.
The list is published every six months by German Professor Hans Meuer and US-based Professor Jack Dongarra.
Dongarra told the BBC it was unlikely that another manufacturer would overtake IBM in the next year. “Sequoia is very impressive,” he said.
“Substantial planning went into this. We knew the day would come,” David Turek, vice-president of deep computing at IBM, told the BBC. He said his company had been preparing to retake the top spot for two years.
Sequoia is 1.55 times faster than the Fujitsu model, and uses over 1.5 million processors. In comparison the Japanese model has fewer than half the number of central processing units.
What this means is Sequoia is capable of calculating in one hour what otherwise would take 6.7 billion people using hand calculators 320 years to complete if they worked non-stop.
The IBM supercomputer is also more energy efficient than the Fujitsu model. Sequoia consumes 7.9 megawatts compared to the K computer which uses 12.6 megawatts.
Turek described Sequoia as the “pinnacle of energy efficiency” and said the reaction had been “very enthusiastic”.
“Government laboratories in Europe have already expressed interest,” he said.
Sequoia is installed at the US Department of Energy's Lawrence Livermore National Laboratory in California. It will be used to carry out simulations to help extend the life of ageing nuclear weapons, avoiding the need for real-world underground tests.