Interesting. The compilation speeds are probably not surprising, I am guessing that is mostly a function of how much faster process creation/forking is under Linux.
Would be interesting to see this on a more modern kernel, I believe this older LTS Ubuntu uses Kernel 4.15, I’m sure they’ve back ported some security fixes etc but it won’t be the same as running the current stable kernel (5.2.3), perhaps a test on the current stable Fedora release with Kernel-ml from Elrepo would be a more fair / up-to-date test.