by the way the cheapy is now with a c300a@450, 4.5x100, using the b21 trick, in manual cpu setting it has 100, 103, 112, 133 and multiplier to choose up to 8x.
when i put the c566 with the slotket, in manual setting put it at max 8x ,i don't see 100 or higher, but 83 and lower. i think this cause by the limitation of the multiplier.