Linux memory management is actually quite good. In particular the unified fs cache. I would think this guy had weird settings/tweaks and or more things enabled

Linux memory management is actually quite good. In particular the unified fs cache. I would think this guy had weird settings/tweaks and or more things enabled since he ran gentoo but misconfigured swapiness. The apps code is very close and linux doesnt magically needs to allocate more memory. What changes is just libc. Freebsd is one of my favorite OSes regardless.