not so much a question of which computer (although you need a reasonably fast
one to get them to play stutter-free), but rather screen.
if you watch on a reasonably modern monitor (1280x1024 or higher) or even better
on an hdtv with a proper connection (vga/dmi/hdmi not s-video or scart or some
shit like then) and you still can't see the difference, i would suggest visiting
an eye-doctor.