> If you have a LOT of ram, compiling on a RAM disk might speed things up by reducing
> disk I/O, but you'd have some overhead from initially copying the source tree to the
> RAM disk before building.
Well, with needing roughly a gigabyte per compile thread, you'll end up needing even more RAM than for just the scratch disk. Plus, using a RAM disk would lower the amount of memory bandwidth available for use by the compile threads, so it could end up being a wash or even slower.