Up this morning are benchmarks comparing the performance of Debian GNU/Linux 7.0 to Debian GNU/kFreeBSD 7.0, the version of the Debian operating system that ships the GNU user-land but replaces the Linux kernel from that of FreeBSD 9.0.
Debian Linux 7.0 uses the Linux 3.2 kernel while Debian kFreeBSD 7.0 uses the FreeBSD 9.0.2 kernel. The user-lands were basically the same across each Debian release and all testing happened from a Lenovo ThinkPad T61 with Intel Core 2 Duo T9300 CPU with NVIDIA Quadro graphics. All of the system hardware/software details, logs, and benchmark results are hosted on OpenBenchmarking.org within 1306092-UT-KFREEBSDD77.
See the rest of the results on OpenBenchmarking.org. The results show that when testing on the same hardware, Debian GNU/Linux 7.0 with the Linux 3.2 kernel is generally faster than Debian GNU/kFreeBSD 7.0 with the FreeBSD 9.0.2 kernel. Again, it's pretty much the same user-land, including the GCC compiler. While the results in this article are just from a lone Intel Core 2 Duo system, other testing carried out at Phoronix has confirmed these findings too of Debian with the Linux kernel being a bit faster than the FreeBSD kernel.