Interal clock (GHz) problem?

My computer is a windows 8 Specs are: AMD A8 APU with Radeon(tm) HD Grapics 1.9 ghz 8gb of RAM 64bit operating system x64 based processor LAPTOP The problem I having is related to the GHz. My computer can run 1.9 GHz but when I check it is only running at 850 MHz. This is under half and I can really see the FPS issues in all the games I play. When I originally got the laptop it was running smoothly with all the games now it's really slowed down. For example, I was able to run COH on medium settings with no lag, now it's unbelievably laggy. On top of that I was able to run Skyrim on high with minimal FPS drops now it has troubling running on the medium preset. I have defragged, uninstalled unused software, clean my pc and run regular virus scans. My personal theory is that is this issue is caused by some fan power saving option that I cannot find anymore