Which uses RAM more efficiently?

[M A V I C]

N-OS X-tasy! wrote:
One little-known factoid about OS X is that each icon on the desktop is actually a separate open window and is treated as such by the OS. Having multiple icons on your desktop (not to mention on the desktops of other logged-in user accounts) can quickly eat up system resources.

Is that just in Leopard? That would explain why I've had much better performance and uptime since installing Hazel.