See here. They ran Word and Excel to see if today’s machine is any better than what we had 20 years ago. Money quote: “When we compare strictly common, everyday, basic user tasks between the Mac Plus and the AMD we find remarkable similarities in overall speed, thus it can be stated that for the majority of simple office uses, the massive advances in technology in the past two decades have brought zero advance in productivity. And that’s just plain crazy.”
CORRECTION: The AMD machine in the test was running XP, not Vista. My bad. Sorry.