to do this you would have to either bring your fsb/ram multiplier down (it may say somewhere ddr2-800, 667, 533, 400, or whatever, and change that to the next one lower) or you can loosen your ram timings. I'm not sure where they are on your board but on mine I have to go into advanced/cpu settings/ram settings. If you want to find the max OC of your CPU, it is better to bring your ram way down and then overclock until it's unstable. After that you can bring the fsb down a little and bring your ram mulitplier up until it gives you errors, finally after that you can tighten/loosen your ram timings for best preformance.