AMD 3000 only booting with a FSB of 233

[LizardKing]

Hi
I need some advise on this little problem
Mb is a asrock k7 something
The chip only seems to beable to boot at 233mhz and then thats only 1 out of 5 trys or so. Whenever the FSB is changed to 333mhz it wont post at all and reverts back to 233mhz
At 1st i thought it was the MB but thats been replaced with a MSI KT6V but that wont even post at the default bios settings.
Every part of the PC has been swapped out for different parts all with the same results so its deffenetly the chip

Is this going to be a RMA job?
cheers

 

[LizardKing]

Just to clear a few things up as that was worded badly! was half cut when wrote
The cpu is a 166fsb, but is only posting at 133fsb
The motherboard does support 166 as it use to run at 166 fine, its just recently thats its decided to revert back to 133.
cheers