Like as already been said, you cannot change the multi on that old processor either up or down. What you can do is overclock the fsb speed. Does that old Shuttle board have fsb and vcore adjustments in bios? If so, that would be the easiest way to overclock it. If it doesn't have them in bios, then I believe you can do a pinmod so that your board senses the processor as a 133 fsb part, which would boost it to 2667 MHz.