I don't know about that, it depends on the build tree I guess. Our IDE build tree (which includes compiler, RTL and lots of other stuff) writes about 600M of intermediate files, 1G of executables / debugger symbol files / map files etc., and reads probably several G worth of source. A rebuild (clean and build) currently runs in about 13 minutes on my 10K drive, but I'm fairly sure it could be cut down with faster I/O.