For the Embarrassingly Parallel test with the NAS Parallel Benchmark from NASA, Ubuntu 12.04 LTS had a performance advantage. Ubuntu 12.04 LTS was the leader even while all tested platforms were using a GCC 4.6 compiler.
For the LU NPB test, Ubuntu 12.04 LTS and Debian GNU/Linux Wheezy were performing the same, but Debian GNU/kFreeBSD was far behind. Debian GNU/kFreeBSD was running at just about 20% the speed of the Linux distributions.
For the MG test, Debian GNU/kFreeBSD lost again, but it was not to the extreme loss found in LU.A.
Similarly, Debian GNU/kFreeBSD for this OpenMP benchmark was slower than Debian GNU/Linux even with the nearly identical user-space.