I co-worker just pointed this out. On my Powerbook (a G4/550, 768 MB, 40 GB 4200 RPM drive), running ‘find /usr’ takes around 30 seconds every time I run it:
tibook$ time find /usr | wc 48402 48402 2390367 real0m30.041s user0m0.410s sys 0m2.620s tibook$ time find /usr | wc 48402 48402 2390367 real0m32.034s user0m0.450s sys 0m2.710s
On the other hand, one of my Linux boxes at home isn’t that much faster (Athlon 700, 384 MB, old Maxtor 5 GB drive), but it’s able to do repeated finds much quicker:
debian# time find /usr | wc 124088 124108 5869110 real1m43.631s user0m0.680s sys 0m1.170s debian# time find /usr | wc 124088 124108 5869110 real0m2.090s user0m0.530s sys 0m0.700s
Notice that repeated finds drop from 103 seconds to 2 seconds on the Linux box, while they stay around 30 seconds on the Mac, even though the Mac has twice the RAM of the PC.
I’m assuming that OS X is restricting the amount of RAM used for disk caching, but it’s really painful in this case.