Worse, a bunch of applications had code that would set up window locations with the assumption that the window borders were 1 pixel wide, like they were prior to Mac OS 8. Modern Mac OS X is actually quite efficient, with zero-pixel window borders on three sides, and narrower scroll bars. Try running at a more modest 800圆00 or 640x480 and it will seem less efficient.
The fat borders for the windows and the control strip at the bottom left of the screen took up a lot of space on real monitors of the era.