SiS 486SOM Socket 3 486 AT Motherboard SiS 85C496 Chipset ISA System Board

SiS 486SOM Socket 3 486 AT Motherboard SiS 85C496 Chipset ISA System Board

The SiS 486SOM is a Socket 3 AT-form-factor system board built around the SiS 85C496 chipset, designed to support the 486 generation of processors from Intel, AMD, and Cyrix. It is a full AT-size board with an ISA expansion bus and multiple SIMM memory banks, representative of the mainstream desktop platform of the mid-1990s.

Specifications & What's Included

• Model: 486SOM (board marking: 486SOM M102)
• Manufacturer: SiS (Silicon Integrated Systems)
• Chipset: SiS 85C496 (date code 9615, ©SIS 1995)
• CPU Socket: Socket 3 (ZIF, supports 486 SX/DX/DX2/DX4 and compatible CPUs)
• Form Factor: AT
• Expansion Bus: ISA (multiple full-length ISA slots; no PCI)
• Memory: SIMM slots (multiple banks for 30-pin and/or 72-pin SIMMs)
• Storage interfaces: IDE and floppy headers on board
• Keyboard connector: DIN-5 (AT-style)
• Board only — no CPU, memory, or cables included

Applications

Socket 3 AT motherboards like the 486SOM were the standard desktop platform through the mid-1990s, supporting the 486 processor family at a time when that CPU was the workhorse of office and home computing. The SiS 85C496 was a popular single-chip 486 system controller that integrated the CPU bus interface, cache controller, DRAM controller, and ISA bus bridge into one package, keeping board costs low. These boards ran MS-DOS, Windows 3.x, and early Windows 95, and were used in everything from business workstations to point-of-sale terminals. Today they are sought by vintage computer enthusiasts and collectors rebuilding or maintaining 486-era systems, and by industrial and embedded users who still operate legacy 486-based equipment. The pure ISA bus (no PCI) places this board in the earlier segment of the Socket 3 generation, before PCI became standard on 486 boards in 1993–1994.