An interesting link for the upcoming EL5. http://www.redhatmagazine.com/2007/02/16/winning-benchmarks-before-its-released-red-hat-enterprise-linux-5/ OpenMP is a standard with precompiler directives for multithreading. From what I recall from my previous W*ndows programming days it was for Fortran and C++. I haven't checked if it is provided for other languages since then, but anyway. :-) In any case, it is about the programmer providing specific multithreading guarantees about the execution of specific code. BTW, I read in a Fedora web page that they compile its binaries with specific flags. Are the flags used for compiling SL the same as the flags used for EL?