I experience the same. I got an i5-3570 that boosts all the way to 4.8 GHz. That is a CPU that isn't overclockable and I got a B75 MOBO which doesn't allow tweaking, so it's kinda strange. http://peecee.dk/uploads/022013/Unavngivet16.png
- As you can see on this picture.
I begin to see a lot of threads of such issues lately on the forum. I myself have posted a couple. My only advice is to keep monitoring temperatures and look out for strange performance issues. If you don't spot anything, then stop to worry. If temperatures become a problem, then reapply your cooler with some decent thermal paste, or get an aftermarket cooler to do the job.