A Chinese scientific research center has built the fastest supercomputer ever made, replacing the United States as maker of the swiftest machine, and giving China bragging rights as a technology superpower.

The computer, known as Tianhe-1A, has 1.4 times the horsepower of the current top computer, which is at a national laboratory in Tennessee, as measured by the standard test used to gauge how well the systems handle mathematical calculations, said Jack Dongarra, a University of Tennessee computer scientist who maintains the official supercomputer rankings.

Although the official list of the top 500 fastest machines, which comes out every six months, is not due to be completed by Mr. Dongarra until next week, he said the Chinese computer “blows away the existing No. 1 machine.” He added, “We don’t close the books until Nov. 1, but I would say it is unlikely we will see a system that is faster.”

Officials from the Chinese research center, the National University of Defense Technology, are expected to reveal the computer’s performance on Thursday at a conference in Beijing. The center says it is “under the dual supervision of the Ministry of National Defense and the Ministry of Education.”