Cpu External Clock Jumpers; Cpu Type Jumpers - Intel 486MIS Quick Start Manual

CPU External Clock Jumpers

If you are installing an i486DX, or i486SX the internal CPU clock speed is
the same as the external CPU clock speed. This is different for i486DX2
CPU where the external speed is one-half of the internal speed. For
example, a 486DX2-66 has an external clock speed of 33MHz.
CPU External
Clock Speed
20MHz
25MHz
33MHz
40MHz
50MHz

CPU Type Jumpers

CPU Type
486DX, 486DX2
487SX, ODP486SX
486SX
Cyrix 486DLC
Care should be taken when installing the CPU into the Pin Grid Array
(PGA) socket on the system board. Make certain that pin 1 of the CPU
chip is correctly aligned with pin 1 of CPU socket. The location of pin 1
on the CPU is denoted by a small notch.
Page 8
JP3 JP4
OPEN SHORT
SHORT OPEN
SHORT SHORT
OPEN OPEN
OPEN SHORT
JP1 JP2
1-2 1-2, 3-4
2-3 1-2, 3-4
OPEN 2-3
OPEN 2-3
486MIS System Board User's Manual
JP5 ID3
SHORT 1-2
SHORT 1-2
OPEN 1-2
SHORT 2-3
OPEN 2-3
JP18
1-2
1-2
1-2
2-3