uhh... im just guessing.
but the new chipset supports 133FSB, im guessing they come unlocked, because you have to use a different multiplyer to run at default speed with 133Mhz FSB compaired to 100Mhz FSB.
Just a guess.
Easyer and smarter then doing like intel and selling 2 different chips for 100Mhz/133Mhz BUS