3dfx_fan wrote on 2025-09-23, 10:08:

I have similar problem to this:
Pentium 3 500 won't hit 500mhz?!
But in my case Pentium III 500Mhz does not work with Asus P3B-F completely at all at any FSB speed (does not matter if using junpers or jumperfree), while this CPU (Pentium III 500Mhz) works on another motherboard. My P3B-F seems to start fine with Pentium II 333MHz and Pentium III 450Mhz, but not with Pentium III 500Mhz. This motherboard has also broken PS/2 mouse port and PS/2 mouse don't work ("!" in yellow triangle id device manager) and I use USB mouse, but that should have nothing to do with CPU problems.

I suppose the motherboard works with another CPU, I have a similar problem with a motherboard, in my case a Soyo BX, it works with the Celeron FSB 66, and also with the Celeron overclock to FSB 100, it also works with a PII 300/66, any CPU FSB 100 or 133 does not work, even using Slot1 370 adapters, it could probably be a problem of contacts of the Slot1, or other, maybe try to clean the contacts of the CPU PIII 500, or spray a deoxidist, even a cleaning of the Slot1 (contacts), could improve the contact between CPU and Slot 1, if you're lucky 🍀, it could work.

3dfx_fan wrote on 2025-09-23, 10:08:

I have similar problem to this:
Pentium 3 500 won't hit 500mhz?!
But in my case Pentium III 500Mhz does not work with Asus P3B-F completely at all at any FSB speed (does not matter if using junpers or jumperfree), while this CPU (Pentium III 500Mhz) works on another motherboard. My P3B-F seems to start fine with Pentium II 333MHz and Pentium III 450Mhz, but not with Pentium III 500Mhz. This motherboard has also broken PS/2 mouse port and PS/2 mouse don't work ("!" in yellow triangle id device manager) and I use USB mouse, but that should have nothing to do with CPU problems.

https://theretroweb.com/motherboards/s/asus-p3b-f#chips
https://theretroweb.com/chip/documentation/as … 81946939863.pdf

Pins 81 and 84: measure when cpu is PIII-500 and other working cpus. See if there ia a vcore consistent ok value for the working cpus.
Pins 72-76: VID0-4

Could be detecting incorrectly and one of these is abnormally low or high...

Wild guess.