Hey, I've got a INTEL Dual Core 5200, which is 2,50GHZ, I downloaded a program called CPU-Z and according to it, my cpu speed is 1,20ghz, HEEELP
Actually from the link below, the cpu should work at 2.50Ghz.
Try this utility to see if it makes any difference
If you are using an Intel Board, try this software as well:
If it is not Intel board, check with the board manufacturer if there is anything from their side that can fix or possibly a bios which can fix this.
All the best,