DELL COMPUTER CORPORATION
Precision 486SX/25, 486DX/33, 486DX2/50
| 
 Processor  | 
 80486SX/80487SX/80486DX/80486DX2  | 
| 
 Processor Speed  | 
 25/33/50MHz  | 
| 
 Chip Set  | 
 OPTI  | 
| 
 Max. Onboard DRAM  | 
 64MB  | 
| 
 Cache  | 
 64/256KB  | 
| 
 BIOS  | 
 AMI  | 
| 
 Dimensions  | 
 330mm x 218mm  | 
| 
 I/O Options  | 
 Bus mouse port, floppy interface, IDE interface, parallel port, proprietary expansion module, serial ports (2), VGA port  | 
| 
 NPU Options  | 
 None  | 
| 
 CONNECTIONS  | |||
| 
 Purpose  | 
 Location  | 
 Purpose  | 
 Location  | 
| 
 Internal battery holder  | 
 BAT  | 
 Serial port 1  | 
 J10  | 
| 
 Proprietary expansion module  | 
 EXP  | 
 IDE interface LED  | 
 J23  | 
| 
 Bus mouse  | 
 J1  | 
 Reset switch  | 
 J24  | 
| 
 IDE interface  | 
 J5  | 
 Speaker  | 
 J25  | 
| 
 Floppy drive interface  | 
 J6  | 
 Power LED & keylock  | 
 J26  | 
| 
 Parallel port  | 
 J8  | 
 VGA port  | 
 J27  | 
| 
 Serial port 2  | 
 J9  | ||
| 
 USER CONFIGURABLE SETTINGS  | |||
| 
 Function  | 
 Jumper  | 
 Position  | |
| » | 
 Monitor type select color or monochrome VGA  | 
 W1  | 
 pins 1 & 2 closed  | 
| 
 Monitor type select monochrome  | 
 W1  | 
 pins 2 & 3 closed  | |
| » | 
 CMOS memory normal operation  | 
 W2  | 
 pins 1 & 2 closed  | 
| 
 CMOS memory clear  | 
 W2  | 
 pins 2 & 3 closed  | |
| » | 
 CPU clock source select SYSCLK/1  | 
 W3  | 
 pins 1 & 2 closed  | 
| 
 CPU clock source select SYSCLK/2  | 
 W3  | 
 pins 2 & 3 closed  | |
| » | 
 VGA port enabled  | 
 W10  | 
 pins 1 & 2 closed  | 
| 
 VGA port disabled  | 
 W10  | 
 pins 2 & 3 closed  | |
| 
 DRAM CONFIGURATION  | ||||
| 
 Size  | 
 Bank 0  | 
 Bank 1  | 
 Bank 2  | 
 Bank 3  | 
| 
 1MB  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 2MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
| 
 3MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 NONE  | 
| 
 4MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
| 
 4MB  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 5MB  | 
 (1) 1M x 36  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
| 
 6MB  | 
 (1) 1M x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 NONE  | 
| 
 8MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
| 
 9MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 256K x 36  | 
 NONE  | 
| 
 10MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
| 
 12MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 16MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 16MB  | 
 (1) 4M x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 17MB  | 
 (1) 4M x 36  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
| 
 18MB  | 
 (1) 4M x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 NONE  | 
| 
 20MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
| 
 24MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 32MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
 NONE  | 
| 
 33MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 256K x 36  | 
 NONE  | 
| 
 34MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
| 
 36MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 40MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 48MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
| 
 64MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
| 
 CACHE CONFIGURATION  | |
| 
 Size  | 
 Bank 0  | 
| 
 64KB  | 
 (8) 8K x 8  | 
| 
 256KB  | 
 (8) 32K x 8  | 
| 
 CACHE JUMPER CONFIGURATION  | |||
| 
 Size  | 
 W4  | 
 W5  | 
 W9  | 
| 
 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  | 
 W6  | 
 W7  | 
 W8  | 
| 
 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  | 
| 
 VGA REFRESH CONFIGURATION (800 X 600 RESOLUTION)  | |||
| 
 Refresh Rate  | 
 SW1/1  | 
 SW1/2  | |
| 
 56Hz  | 
 Off  | 
 Off  | |
| 
 56Hz  | 
 On  | 
 On  | |
| » | 
 60Hz  | 
 Off  | 
 On  | 
| 
 72Hz  | 
 On  | 
 Off  | |
| 
 VGA REFRESH CONFIGURATION (1024 X 768 RESOLUTION)  | |||
| 
 Refresh Rate  | 
 SW1/3  | 
 SW1/4  | |
| » | 
 Interlaced  | 
 Off  | 
 Off  | 
| 
 60Hz  | 
 Off  | 
 On  | |
| 
 70Hz  | 
 On  | 
 Off  | |
| 
 72Hz  | 
 On  | 
 On  | |
| 
 VGA REFRESH CONFIGURATION  | |||
| 
 Refresh Rate  | 
 SW1/5  | ||
| » | 
 31.5Hz horizontal, 60/70Hz vertical  | 
 Off  | |
| 
 40Hz horizontal, 75/80Hz vertical (see note)  | 
 On  | ||
| 
 Note :Use 75Hz for video modes 0 through 10h and 13h. Use 80Hz for video modes 11h and 12h.  | |||
| 
 VRAM CONFIGURATION  | ||
| 
 Size  | 
 Bank 0  | |
| » | 
 512KB  | 
 NONE  | 
| 
 1MB  | 
 (4) 44256 ZIPPs  | |
| 
 VRAM SWITCH CONFIGURATION  | ||
| 
 Size  | 
 SW1/6  | |
| » | 
 512KB  | 
 On  | 
| 
 1MB  | 
 Off  | |