In the latest rankings, the new number three supercomputer is the upgraded Piz Daint, a system installed at the Swiss National Supercomputing Center.

Its current performance of 19.6 petaflops pushed Titan, a machine installed at the US Oak Ridge National Laboratory, into fourth place. Titan's performance of 17.6 petaflops has remained constant since it was installed in 2012.

"This is the second time in the 24-year history of the TOP500 list that the United States has failed to secure any of the top three positions," the TOP500 organizers said in a statement.

The only other time this occurred was in November 1996, when three Japanese systems captured the top three spots.

"Nevertheless, the US still claims five of the top 10 supercomputers, which is more than any other nation," they said.

Fu called the upgraded Swiss system "really a surprise," saying that "it reflects the increased investment in large-scale supercomputers in Europe."