The performance of the world's fastest computers has been steadily growing for two decades, but the latest tally of their collective performance shows slowing progress.
On the Top500 list of the fastest supercomputers, which a group of researchers update twice each year to coincide with supercomputing conferences, the combined performance of all the machines increased from 250 petaflops in November 2013 to 274 petaflops in June 2014.
That's "a noticeable slowdown in growth," the Top500 researchers announced Monday.
The petaflops measurement counts quadrillions of floating-point mathematical calculations per second. For the third list update in a row, the, is the No. 1 system. It has a calculation rate of 33.86 petaflops, or 33,860,000,000,000,000 floating-point operations per second.
Supercomputers are used for demanding computational tasks such as simulating nuclear weapons explosions, modeling the earth's climate, predicting aircraft aerodynamics, reproducing the physical functioning of biological brains, and studying materials at the molecular level. The machines typically occupy many cabinets and consume huge amounts of electrical power.
Tianhe-2 and other mammoth high-ranking supercomputers have kept the total performance of the list growing, but lower down in the rankings, the growth has slowed, suggesting that market dynamics are different for the top machines and the merely very impressive.
"The performance of the last system on the list (No. 500) has consistently lagged behind historical growth trends for the past five years," the Top500 organizers said. That machine's performance increases at a rate of 55 percent each year right now. But between 1994 and 2008, the 500th system's performance was increasing at a rate of 90 percent per year.
"Recent installations of very large systems until June 2013 have counteracted the reduced growth rate at the bottom of the list," the researchers said. "This offers an indication that the market for the very largest systems might currently behave differently from the market of mid-sized and smaller supercomputers."
The US remains the top supercomputer user, with 233 of the 500 systems, but that dropped over the last half year from 265. China's presence on the list increased from 63 to 76 supercomputers. That nearly matches the major European buyers' total: the UK has 30, France has 27, and Germany has 23.
Intel supplies processors for the lion's share of the systems -- 427 of them, to be precise. IBM's Blue Gene/Q technology, though, which uses Big Blue's own Power processors, has a heavy footprint at the top of the list. Blue Gene/Q systems ranked No. 3, 5, 8, and 9 among the top 10.