Compilation taking multiple hours - how to speed up? in How Do I? Posted May 31, 2017 · Report reply Found a really simple solution - use a ramdisk :-) I put a process monitor on the compiler as it was running, and it seems to be spending most of time on IO - I would have attached a picture of the procmon trace, but for some reason the forum isn't letting me upload any pictures. Basically the compiler appears to open, write to, and close sym.pdb, bod.pdb and rdf.pdb (plus others) over and over again. Each open and close results in an IO flush. On my conventional spinning-rust hard disk this results in a huge overhead just waiting for lots and lots of tiny synchronous IO operations to complete. So I created a small ramdisk, put the project files on there, and tried compiling... and instead of compilation taking hours or days, it now only takes minutes. Unbelievably quick compared to before -- compiling the whole project now takes around ~10 minutes.