XP may feel bigger, but it manages resources much better than the 9x predecessors. I benchmarked three old P2/266's at work, each with 64 megs of ram. I don't remember the numbers, but with minimal installs, XP was the fastest, 95OSR2 in the middle, and NT4 at the bottom.
I might mention that the boot times were in the same order, XP being the fastest. XP also runs on the newer NT core, and not the shotty old w32 core that has taken way too long to die. The IP stack is also taken from it's NT brethren.
One of my goals is to find the slowest machine that I can get XP to run on. So far an ancient 166 at work (48mb ram) has been it.
