I have a piece of multi-threaded software which runs at different speeds under the latest ubuntu server, redhat enterprise and CentOS - all installed on the exact same server for comparison.
Ubuntu server was slowest, followed by CentOS and then redhat enterprise. The difference was 10-20%.
The difference between centOS and redhat might be exaplined by a newer gcc version, but at least in the last two operating systems the same version of gcc was used.
What I could see in the ubuntu run is that although the program used, say, 13 cores, the total CPU reported by "top" was about 1220%, while on redhat (and centOS) it was 1300%
Does anybody have an explanation? I prefer to work with Ubuntu (it's free), but I cannot afford the slow-down. I tried other multithreaded benchmarks which seemed to also indicate that ubuntu is somewhat slower - on the same downloaded executable, not compiled locally.