OK, now I'm impressed. I've heard of it before, but never actually looked deeper.
From Vista Features Explained:
"A new memory management technology in Windows Vista, Windows SuperFetch,
helps keep the computer consistently responsive to your programs by
making better use of the computer's RAM. Windows SuperFetch prioritizes
the programs you're currently using over background tasks and adapts to
the way you work by tracking the programs you use most often and
preloading these into memory. With SuperFetch, background tasks still
run when the computer is idle. However, when the background task is
finished, SuperFetch repopulates system memory with the data you were
working with before the background task ran. Now, when you return to
your desk, your programs will continue to run as efficiently as they
did before you left."
Ray Booysen
ray@vistasquad.co.uk