Precision 486SX/25, Precision 486DX/33 Motherboard Settings and Configuration

Processor	80486SX/80487SX/80486DX
Processor Speed	25/33MHz
Chip Set	OPTI
Max. Onboard DRAM	32MB
Cache	64/256KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	None
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
Reset switch	J9	Speaker	J21
External battery	J18	Power LED & keylock	J22
Turbo switch	J20
Note:Although there is a 4167 socket on the board, it is not supported. (As per the manufacturer)

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Battery select internal	W1	Closed
	Battery select external	W1	Open
»	CMOS memory normal operation	W2	pins 1 & 2 closed
	CMOS memory clear	W2	pins 2 & 3 closed
»	CPU speed select ATCLK/4	W3	pins 2 & 3 closed
	CPU speed select ATCLK/6	W3	pins 1 & 2 closed
»	Factory configured - do not alter	W8	Open
»	Factory configured - do not alter	W9	Open
»	Factory configured - do not alter	W10	Open
»	Monitor type select color	W12	pins 1 & 2 closed
	Monitor type select monochrome	W12	pins 2 & 3 closed
»	Factory test disabled	W13	Open
	Factory test enabled	W13	pins 1 & 2 closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1
1MB	(4) 256K x 9	NONE
2MB	(4) 256K x 9	(4) 256K x 9
4MB	(4) 1M x 9	NONE
5MB	(4) 1M x 9	(4) 256K x 9
8MB	(4) 1M x 9	(4) 1M x 9
16MB	(4) 4M x 9	NONE
20MB	(4) 4M x 9	(4) 256K x 9
32MB	(4) 4M x 9	(4) 1M x 9

CACHE CONFIGURATION
Size	Bank 0
64KB	(8) 8K x 8
256KB	(8) 32K x 8

CACHE JUMPER CONFIGURATION
Size	W8	W9	W18
64KB	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed
256KB	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed

CPU TYPE CONFIGURATION
Type	W5	W6	W7
80486SX	pins 2 & 3 closed	pins 2 & 3 closed	Open
80487SX	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed
80486DX	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed