When running Fhourstones, which is a complex Connect-4 solving benchmark, Ubuntu 9.10 was just under 12% faster than FreeBSD 8.0.
Between FreeBSD 8.0 and Ubuntu 9.10 Alpha 6, the BSD operating system did substantially better. However, this is to no surprise as with Ubuntu 9.10 using the Linux 2.6.31 kernel and EXT4 file-system we have witnessed some performance regressions with SQLite when carrying out database insertions. UFS on FreeBSD is not impacted by these problems.
With the OpenMP-powered Stream memory benchmark, Ubuntu 9.10 Alpha 6 did much better than FreeBSD 7.2 and FreeBSD 8.0 -- to the extent of being over 89% faster with the memory copy operation.