With the embarrassingly parallel EP.B workload from NPB, Arch Linux was the fastest Linux distribution followed by Fedora 17 and then Ubuntu 12.04 LTS.
For the Multi-Grid MG.B memory-intensive benchmark in NASA's NAS Parallel Benchmarks, Arch Linux and CentOS were slightly ahead of the other three Linux distributions for being the fastest.
For the Scalar-Penta-diagonal solver in NPB, Ubuntu 12.04 LTS and CentOS 6.2 were the fastest operating systems.
Lastly, with NPB's "Unstructured Adaptive mesh, dynamic and irregular memory access" test case, CentOS 6.2 was the fastest followed by Fedora 17 and then Arch Linux. Ubuntu 12.04 LTS and Slackware 14 Beta tied behind them.
CentOS 6.2 won again, this time for the MPI-based FFTE test profile.