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 [Image] CONNECTIONS Purpose Location Purpose Location Internal battery BAT Serial port 1 J10 holder Proprietary expansion EXP IDE interface LED J23 module Bus mouse J1 Reset switch J24 IDE interface J5 Speaker J25 Floppy drive J6 Power LED & keylock J26 interface Parallel port J8 VGA port J27 Serial port 2 J9 USER CONFIGURABLE SETTINGS Function Jumper Position » Monitor type select color or W1 pins 1 & 2 monochrome VGA 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 NONE NONE NONE 36 2MB (1) 256K x (1) 256K x NONE NONE 36 36 3MB (1) 256K x (1) 256K x (1) 256K x NONE 36 36 36 4MB (1) 256K x (1) 256K x (1) 256K x (1) 256K x 36 36 36 36 4MB (1) 1M x 36 NONE NONE NONE 5MB (1) 1M x 36 (1) 256K x NONE NONE 36 6MB (1) 1M x 36 (1) 256K x (1) 256K x NONE 36 36 8MB (1) 1M x 36 (1) 1M x 36 NONE NONE 9MB (1) 1M x 36 (1) 1M x 36 (1) 256K x NONE 36 10MB (1) 1M x 36 (1) 1M x 36 (1) 256K x (1) 256K x 36 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 NONE NONE 36 18MB (1) 4M x 36 (1) 256K x (1) 256K x NONE 36 36 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 NONE 36 34MB (1) 4M x 36 (1) 4M x 36 (1) 256K x (1) 256K x 36 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 pins 2 & 3 pins 2 & 3 closed closed closed 256KB pins 1 & 2 pins 1 & 2 pins 1 & 2 closed closed closed CPU TYPE CONFIGURATION Type W6 W7 W8 80486SX pins 2 & 3 pins 2 & 3 Open closed closed 80487SX pins 1 & 2 pins 1 & 2 pins 1 & 2 closed closed closed 80486DX pins 1 & 2 pins 1 & 2 pins 2 & 3 closed closed 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 On note) 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