That rig should be doing pretty well. What are you compiling?
Some things to consider...
- Turn off expensive optimizations during the devel/debug cycle.
- Look into pre-compiled headers
- Look at your source tree wrt header file dependencies. If you have a few big headers that everything depends on, that means every time you change that header all the dependencies get rebuilt also. Consider smaller, more specialized headers.
- You've got alot of RAM and CPU there. How's your disk looking? Compiling can be failry disk intensive.
- Patience - build cycles are a good time to double check things, or just go grab a dew.