Hmmm... very strange. What does the post screen identify the CPU as? There is no such thing as a Pentium III 466, only 450,500,550 etc. under User Define you should be able to manually set all those parameters. What does it do when you say it doesnt work?Does it post and boot at all? I have the same Mobo running a PIII 550E on it and the 1st time I put it in(after flashing the BIOS) it posted as a 366 but I was able to set it up correctly manually immediately. I now have it running at 733 quite well after some tweaking

Is it a slot1 or an FC/PGA model?
If it is FC/PGA, then what type of Slotket adapter are you using? I have heard of problems with some adapters but they all have to do with voltage, never wrong CPU parameters. Please let us know and we should be able to get it straightened out.
kbman