Well here is my unscientific assessment...
PIII 733mhz, W2k/XP, 256meg ram (with alot of junk running in the background) average time per unit 15hrs 33mins.
Celeron 500mhz, W2k, 192meg ram (not much else running)
average time per unit 15hrs 36mins.
imac 500mhz, 10.0.3, 256meg ram (my...