Are you the type that turns the heat up on high and leave all the lights on in the house they leaves home for the day?
What you are discriping is Intel Speed Step (and turbo boost) technology. If your system is idling away, it clocks the CPU down to slow speed to save power since all it would be doing is bruning power at full speed..
As your work load increases, the speed will increese due to Turbo Boost to several steps faster than the processor rating up to 3.33ghz.
If you can find something that can stress the CPU hard enough all the cores ups to near max, It will drop back down to the rate 3.06Ghz since this is the maximum speed of a i7 950 running all cores at max load. The point were it clocks down is determined by the therimal cooling of your processor as were the the mother board Imon curve.
See here for more details.