Another T-Bird and KX133 Question

[SPAnDAU]

I have heard people saying that the KX133 will not support Thunderbird and Duron processors that are specced at high speeds, >800Mhz. However they say that the motherboard will support the processors if they have been overclocked to that speed.

I don't quite get how there would be a difference since the only difference between the two would be the multiplier.

Can anyone elaborate for me??

Thanks