That's CPU TIME not CAPACITY. If you look at the performance tab, you should see that you're floating between 0%-4% CPU utilization. 98% of the time, your CPU isn't doing anything, so NT-based OSes issue HALT commands that make the CPU do nothing. Bonus feature is that it'll run cooler as a result. (That's what CPU Idle or Rain did for Win9X OSes, issue the HALT command that they didn't have built in.)