if you have a guide for your mobo look for any part that specifies the jumpers on your mobo. if you are lucky it will have jumper setups for all the different frequencies your board supports. if you dont have a guide then find out your mobo name, you can use cpu-z or dxdiag if im not mistaken to find out mobo name and then search online for a guide. if not try to enter your bios and look for a frequency control item and select the correct one.
if you have a system built by dell or one of those larger companies you may just be ****ed man...
The World is my trashcan and i intend to fill it...