Sephiroth, The Great wrote on 2024-04-27, 11:23:

What would be best CPU for this motherboard?

Probably a P3 600Mhz / 100 FSB Katmai Slot 1

A Coppermine based Pentium III with 100MHz FSB should also work with the Revision 2.2E. A Socket 370 PIII Coppermine (FSB100) would be the cheapest option, because this board has Slot 1 and Socket 370 options. The 1,1GHZ PIII S370 should be the fastest option. I olny would flash to the latest version, because the 1,1Ghz PIII has the latest Coppermine cD0 stepping. People say, that the CPU voltage can also go down to 1,5V, so it could be work, and if not, you get a black screen and can only use a PIII Katmai 600 as the fastest CPU with 2,05V VCore, or you need a Coppermine with the older cC0 Stepping.

You can also try this bios mod tutorial for Coppermine cD0, Tualatin support: https://www.youtube.com/watch?v=VwZT40sRMzM or https://www.youtube.com/watch?v=0KBYj1vx3zQ

Found this in another forum post:
I just checked with the manufacturer. Then you should be able to install an “Intel® Pentium III 850 MHz (Coppermine)”. Only a bios update might be necessary. The manufacturer's specification refers to PCB version 2.2E and BIOS version 50.

However, I don't know whether you can also use a larger CPU.