Chris from AMDZone seems to think he has actual evidence that a 166MHz FSB is supported by the Athlon. The information was found on the AMD website, so it seems pretty believable.

Brian let me know that on page 79 of the Athlon model 8 tech doc the FSB_Sense [1:0] pins have a setting for 166MHz. This would mean that the capability of setting the CPU to a 333MHz FSB is already built in. The question becomes can the current CPUs be tricked into thinking they should run with a 166MHz FSB? If anyone is able to figure this out then please let me know.