Beginning with the C-Ray multi-threaded ray-tracing benchmark, Ubuntu 11.10 with GCC 4.6.1 is just behind Mac OS X 10.7.2 with the each of its compilers. GCC 4.2.1 on Mac OS X 10.7.2 ended up producing faster performance than LLVM/Clang 3.0 in Xcode4.
Compile Bench, which is a mixture of a CPU and disk benchmark, performed roughly the same when it came to the initial creation work.
The actual compile performance was also similar between each OS.
The big difference, however, came down the read compiled tree performance. With the disk accesses, Mac OS X 10.7.2 and its HFS+ file-system was reading much faster than the EXT4 file-system under Ubuntu 11.10.