Bursts; This is normal, especially if doing updates in the background or other maintenance tasks. It is kind of hard to explain...but at certain times your cpu will hit 100 % but only utilize that speed at a certain % of the time. So in your situation, it appears that it is using 3.33 Ghz speed at about 26% of the time.
If after a day or so, and no real change, and a few reboots, then look and see what is using the cpu's time. your utilization is kind of high for not doing anything, but that is probably just because of what I stated in my first sentence or two.