I have had 128MB, 256MB and now 384MB running Windows2000
between 128MB and 256MB,
difference was HUGE, I can feel my comp starts swapping even without much multitasking, essential programs are obviously not 'cached'.
between 256MB and 384MB,
difference is small, but noticable. Obviously there is no swapping at all, and that a LOT of stuff are cached therefore system is VERy responsive