I want to put together a Pentium III tower using a beautiful Coppermine SL3XL CPU I found with a Slot 1 form factor. However, I noticed that many slot 1 motherboards do not officially support Coppermine, or even Pentium III altogether. Would it still be possible to use a Coppermine board in a motherboard that lacks official support, or will it fail catastrophically?
Older slot 1 boards only support 66MHz front-side buses and won’t boot with a Coppermine core.
Coppermines use a 100MHz or 133MHz FSB. Any motherboard officially supporting the latter should also support Coppermine. Motherboards only supporting 100MHz FSB may work with 100MHz FSB Coppermines, or even 133MHz if overclocked, but it’s not guaranteed — for example some 440BX boards won’t boot with a Coppermine.
As far as “catastrophic” failure goes, you won’t damage the hardware...
See the Vogons wiki slot 1 page for details of the various Intel chipsets on slot 1 boards, and their level of compatibility. VIA Apollo boards were common too, and most of those should work with Coppermine.