The Jaguar supercomputer at the Oak Ridge National Laboratory was recently upgraded with new AMD processors that gave it enough performance to move up the top 5 supercomputers list. The Jaguar is a Cray XT5 supercomputer and is now the fastest machine in the world.
Jaguar previously used quad-core AMD processors and was upgraded to 6-core processors. The new upgrade gives the supercomputer a theoretical peak performance of 2.3 petaflops/s. The performance on the Linpack benchmark was 1.75 petaflops/second.
The second place computer on the list is the Roadrunner using dual CPU AMD power. The processors used in the Jaguar are AMD 6100 series parts.