I've got a BX6r2. Just added a Celeron2 633. In the bios, it does not have a setting for the 633. I loaded the chip on an Abit SlocketIII, went into bios and set the chip to the first 100fsb setting(300/100), then set the voltage to user defined, set it at 1.8v. Works fine. The chip's internal clock is set and locked. So the bios will not change that. I just had to figure a way to set the mb fsb to 100. You can do the same.Runs rock stable at 979mhz.