For Windows machine that are part of a Domain, each time a sh is started it will validate the user permission by contacting the machine specify by the LOGONSERVER variable. This add lots of overhead. This can be bypassed by undefining the LOGONSERVER in your Momentics environment setting, or setting it up to your machine name. Go in Windows/Preferences/C++/Build/Environment. Press Add, then add the LOGONSERVER variable, don't specify any value. Then once you are back in the main dialog press the undefine button. You must also set the ""Replace Native Environment with specified one"" option
On my projet make clean has got from 11 seconds to 7. Compile time from 500 secondes down to 378 !!!