Hi Jerry,
yes you're right, that the performance is not the optimum. This is also caused by the network bottleneck. Files have to be moved around. But first I also used distcc, but it is dangerous when non-CentOS systems or mixed 64 and 32-bit systems are in action. In these cases code linkage failes. So I switched to icecc, which first distributes the right compilers (which the system doing the make job has currently installed). There is also someone who compiles with Gentoo on the CentOS cluster with a different gcc version and it works perfectly.
Greetings, Brian.