Well where you change the timings of your ram and everything there should be something similar to Max Ram speed or something similar, At default it is either Auto, or 400(200). You set it to the next lowest being 333(166) I think thats the next lowest. That will underclock your ram, once you start the overclock though it will bring the ram back up some. Then when you hit the 400(200) mhz again go down to the next lowest speed.