First up are the computationally intensive NAS Parallel Benchmarks from NASA, which are very popular with the HPC community.
When beginning with the "embarrassingly parallel" (EP.B) workload, Fedora 17 was the fastest with a small advantage over Ubuntu 12.04 LTS -- Fedora 17 ships with GCC 4.7 where as Ubuntu 12.04 LTS uses GCC 4.6. However, Ubuntu 12.04 LTS with GCC 4.5 was faster than the default GCC 4.6 package in the Precise repository. Ubuntu 12.04 LTS with GCC 4.5 was 7% faster than Solaris 11 Express. Oracle's Solaris operating system ran at about the same speed as CentOS 6.2 for this multi-threaded test. The slowest performer though was Debian GNU/kFreeBSD Wheezy, which was noticeably impaired compared to the Solaris and Linux operating systems.
With the MG.B workload there is less of a spread and Solaris 11 here outperforms Ubuntu 12.04 LTS and Fedora 17, comes in right behind CentOS 6.2, but the surprising winner here is Debian GNU/kFreeBSD.
There are little changes in the SP.A performance between operating systems, but Solaris 11 is able to hold its ground against the Linux competitors.
For UA.A, Solaris 11 performs much slower than the other OS candidates.