Makes your e-peen larger
No srsly though, if you're an average user, you'll likely never see or feel a difference. If you spend a lot of time at the computer converting, modeling, rendering, etc... you'll be saving yourself time. (To some, time is money when it comes to this) If you're a gamer, depending on the game, you'll see higher fps... which is usually minimal unless the game relies heavily on the CPU. Additionally... if you have multiple beast graphics cards, it eliminates the worry of a bottleneck.
Also... is your CPU at 30% load once you minimize the game, or is that actually in-game? I doubt it's slouching that much if you're running those programs at the same time.