I have a FX-3000 Rev: 1.0 motherboard with a i486SX-25 CPU installed and no cache memory (I’ll list more details below). I’m trying to downgrade it to a AM386DX-40 CPU. The problem is that the computer detected it as a 16 MHz processor instead of a 40 MHz. I checked all the jumper settings and BIOS and can’t find why its running at a low clock speed.

Can anyone suggest anything about this problem?

4 MB
No coprocessors installed
BIOS type: 40-0100-001131-00101111-121291-UMCAUTO-F
Diagram/Jumpers settings: http://www.peteweb.com/ftp/user-submitted/us3486.zip