Western Digital WDC90C31 WD90C31A VESA Local Bus VGA Video Card w/ Disks Manual

Western Digital WDC90C31 WD90C31A VESA Local Bus VGA Video Card w/ Disks Manual

The Western Digital WDC90C31 is a VESA Local Bus (VLB) graphics accelerator card designed for 386 and 486-class PCs. It provides VGA video output through a standard DB-15 connector and connects to the host system via the VESA Local Bus — a high-bandwidth 32-bit local bus standard popular in the early 1990s before PCI became dominant. This listing includes the card itself along with its complete original software package and documentation.

Specifications & What's Included

• Make: Western Digital
• Model: WDC90C31 (chip marking: WD90C31A-LR)
• BIOS: WDC 90C31 Ver 523A (visible on BIOS chip)
• Bus Interface: VESA Local Bus (VLB) — 32-bit
• Video Output: DB-15 VGA female connector on rear bracket
• Configuration: 5-position DIP switch block on bracket for hardware setup
• Form Factor: Full-length expansion card
• Compatible OS: MS-DOS, Windows 3.1
• Includes: 3x original 3.5-inch floppy disks — DOS Utility, Windows 3.1 Driver, Supplemental Disk 3
• Includes: Original installation and user manual with board layout, DIP switch settings, jumper settings, and driver installation instructions
• Compatible software listed in manual: AutoCAD 386 (rel. 9–11), AutoShade, Cadvance 2.x, Generic Cadd 3, Lotus 1-2-3, Symphony, PCAD 2.x, VersaCAD, WordPerfect, Word 5.0/5.5

Applications

The WDC90C31 belongs to the VESA Local Bus graphics card generation that emerged in the early 1990s as a faster alternative to ISA-slot video. The VESA Local Bus ran at the processor's local bus speed — typically 33 MHz on 486 systems — giving VLB cards dramatically better throughput than ISA for graphics-intensive tasks like CAD, desktop publishing, and Windows 3.x GUI rendering. Western Digital's 90C31 was specifically marketed toward CAD workstation users, and the manual's software compatibility list reflects this: AutoCAD, Generic Cadd, VersaCAD, and PCAD all appear alongside productivity software. VLB was prevalent roughly from 1992 through 1994, after which PCI graphics cards took over. Today these cards are sought by collectors restoring 486-era DOS/Windows 3.1 machines and by retro-computing enthusiasts building period-correct CAD or gaming systems.