Solution:

The Cyrix MII -300GP CPU is: 66MHz Bus 3.5x 2.9V (Vcore) FAN/HEATSINK REQUIRED Jumper Settings: JP11 CPU voltage setting -> 2.9V 1-2 open 3-4 closed 5-6 open 7-8 open 9-10 closed JP16 Pentium/Pentium MMX single/dual CPU voltage select -> PentiumMMX enabled 1-3 Closed 2-4 Closed JP19 CPU Frequency Ratio -> 3.5 1-2 open 3-4 open 5-6 open Other jumper settings: default settings