425SX/T, 433SX/T, 433DX/T, 450DX2/T, 466DX2/T Motherboard Settings and Configuration

Processor	80486SX/ODP486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed	25/33/50(internal)/66(internal)MHz
Chip Set	Unidentified
Video Chip Set	Unidentified
Maximum Onboard Memory	40MB
Maximum Video Memory	1MB
Cache	64/128/256KB
BIOS	Phoenix
Dimensions	330mm x 218mm
I/O Options	Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA feature connector, VGA port, riser slot
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
VGA port	CN1	Reset switch	CN8
Parallel port	CN2	External battery	J7
Serial port 1	CN3	IDE interface	J17
Serial port 2	CN4	Floppy drive interface	J18
PS/2 mouse port	CN5	VGA feature connector	J21
IDE interface LED	CN6	Riser slot	SL1
Power LED & keylock	CN7

USER CONFIGURABLE SETTINGS
Function		Label	Position
»	Factory configured - do not alter	J9	Pins 1 & 2 closed
»	Factory configured - do not alter	J11	Open
»	Factory configured - do not alter	J13	Pins 1 & 2 closed
»	Factory configured - do not alter	J14	Pins 2 & 3 closed
»	CMOS memory normal operation	J20	Closed
	CMOS memory clear	J20	Open
»	On board video enabled	J28	Pins 2 & 3 closed
	On board video disabled	J28	Pins 1 & 2 closed
»	Factory configured - do not alter	J29	Open
»	Floppy drive write protect disabled	J30	Pins 2 & 3 closed
	Floppy drive write protect enabled	J30	Pins 1 & 2 closed
»	Factory configured - do not alter	J31	Pins 2 & 3 closed
»	Zero wait state enabled	J32	Closed
	Zero wait state disabled	J32	Open

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2
1MB	(1) 256K x 36	None	None
2MB	None	(4) 256K x 9	(4) 256K x 9
2MB	(1) 512K x 36	None	None
4MB	None	(4) 1M x 9	None
4MB	(1) 1M x 36	None	None
5MB	None	(4) 1M x 9	(4) 256K x 9
6MB	(1) 512K x 36	(4) 1M x 9	None
8MB	(1) 1M x 36	(4) 1M x 9	None
8MB	(1) 2M x 36	None	None
8MB	None	(4) 1M x 9	(4) 1M x 9
10MB	(1) 512K x 36	(4) 1M x 9	(4) 1M x 9
12MB	(1) 1M x 36	(4) 1M x 9	(4) 1M x 9
12MB	(1) 2M x 36	(4) 1M x 9	None
16MB	(1) 2M x 36	(4) 1M x 9	(4) 1M x 9
16MB	None	(4) 4M x 9	None

DRAM CONFIGURATION (CON’T)
Size	Bank 0	Bank 1	Bank 2
17MB	None	(4) 4M x 9	(4) 256K x 9
18MB	(1) 512K x 36	(4) 4M x 9	None
20MB	(1) 1M x 36	(4) 4M x 9	None
20MB	None	(4) 4M x 9	(4) 1M x 9
22MB	(1) 512K x 36	(4) 4M x 9	(4) 1M x 9
24MB	(1) 1M x 36	(4) 4M x 9	(4) 1M x 9
24MB	(1) 2M x 36	(4) 4M x 9	None
28MB	(1) 2M x 36	(4) 4M x 9	(4) 1M x 9
32MB	None	(4) 4M x 9	(4) 4M x 9
34MB	(1) 512K x 36	(4) 4M x 9	(4) 4M x 9
36MB	(1) 1M x 36	(4) 4M x 9	(4) 4M x 9
40MB	(1) 2M x 36	(4) 4M x 9	(4) 4M x 9

CACHE CONFIGURATION
Size	Bank 0	Bank 1	TAG	U1
64KB	(4) 8K x 8	(4) 8K x 8	(1) 8K x 8	(1) 64K x 1
128KB	(4) 32K x 8	None	(1) 8K/32K x 8	(1) 64K x 1
256KB	(4) 32K x 8	(4) 32K x 8	(1) 32K x 8	(1) 64K x 1

CACHE JUMPER CONFIGURATION
Size	J16
None	Pins 1 & 2, 3 & 4, 5 & 6, 9 & 10 closed
64KB	Open
128KB	Pins 1 & 2, 5 & 6, 7 & 8 closed
256KB	Pins 1 & 2, 3 & 4, 5 & 6, 9 & 10 closed

VIDEO MEMORY CONFIGURATION
Size	Bank 0	Bank 1
512KB	512KB	None
1MB	512KB	512KB
Note: The size of the video memory chips are unidentified.

CPU SPEED SELECTION
Speed	J26	J27
25MHz	Pins 1 & 2 closed	Pins 2 & 3 closed
33MHz	Pins 1 & 2 closed	Pins 1 & 2 closed
50iMHz	Pins 1 & 2 closed	Pins 2 & 3 closed
66iMHz	Pins 1 & 2 closed	Pins 1 & 2 closed

CPU TYPE SELECTION
Type	J19
80486SX	Pins 1 & 3, 2 & 4 closed
ODP486SX	Pins 1 & 3, 2 & 4 closed
80487SX	Pins 1 & 3, 2 & 4 closed
80486DX	Pins 3 & 5, 4 & 6 closed
ODP486DX	Pins 3 & 5, 4 & 6 closed
80486DX2	Pins 3 & 5, 4 & 6 closed