Turbo boost is a feature that was released with our 1st generation Intel® Core™ processors and with the 2nd generation Intel Core processor have an upgraded version of Turbo Boost. While it is on by default it can be turned off in the Bios. Here is a simple tool that you can run on your system to see when and what kind of boost are you are getting from this technology http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=19105.
Christian Wood
Intel Enthusiast Team