Uses all 8 of my CPU's. Don't know what you're talking about...
No it doesn't.
If you see all of your CPU:s doing some work it's because of Windows switching different program processes to idle CPU threads. Your 8-core CPU (all cores) will certainly not be on 100% load while playing Diablo.
100% load suggests that the game is running slow.
Anything under 100% load is positive. There's simply nothing left to calculate. Your CPU can take it easy, relax a bit, use less power, conserve energy, make it possible for you to alt tab and watch a movie.
All these great things, because Diablo III is already running as fast as it can, it's bottle necked by other components of your PC, and even then, there might simply be nothing left to calculate.
Before asking about this, check this checklist.Is my game running poorly?
No? Then what's the problem?Is my game consistently at a low (below 25) frame rate?
No? Then what's the problem?Is my game running poorly, but my CPU is not at 100%?
If so, it's time to complain.
Also make sure the rest of your hardware can keep up with your CPU.
--A game engine developer, sighing and face palming at the amounts of stupid in this thread.