Any issues in underclocking the frequency of a CPU? I note that some 133FSB processors are cheaper than 100FSB's and thinking of using a fast cheaper cpu in and older board than a more expensive slower one. Slot 1 type P3's.

The multipliers are locked so it cannot clock at rated speed on a 100MHz bus

As stated above, a 600 MHz P3 would only run at 400 Mhz (2/3 rated speed). Is it really worth the loss of performance?

Thanks for the response guys, I'm still a bit confused so I'll ask the question another way. Can I use a P3 866MHZ 133FSB Slot 1 chip on a Slot 1 Board rated at 600 MHZ? ie. the board settings would be 6x multiplier and the board FSB would be 100, so 6x100=600MHZ? A p3 550MHZ 100FSB chip costs $180-$200 AUSTRALIAN I can get hold of a P3 866 for $160 AUST. AUSTRALIAN Thanks.

Rob: The answer is...maybe. Slot 1 P3's up to 600Mhz used a core voltage of 2.0 volts. Faster slot 1 P3's switched to a core voltage requirement of 1.7 volts. Check your board to see if it will go down to this lower voltage and it would also be wise to see if you need to update the BIOS in order to have the board recognize the faster slot 1 cpu's. P3 450-600 was the Katmai core while the slightly smaller Coppermine core was used for P3's above 600Mhz. Many motherboards need a BIOS update in order to recognize the coppermine cpu's. You may want to consider going with a slotket that has ajustable voltage and a Celeron II. I have seen a 1Ghz Celery living comfortably in a older slot 1 Asus P2-99 board.

I thought voltage regulation was taken care of on the board of the P3. My board make no mention of volatge adjustment for this reason. Thanks for your feedback Jeff. I won't move forward on this until I feel comfortable.