UC4915 A AIO © 1994 Elitegroup Computer Systems
The UC4915-A AIO is an integrated 80486 Baby AT motherboard manufactured by Elitegroup Computer Systems (ECS) around 1994 to 1995. Built around a 168-pin Socket 3 infrastructure, the board is driven by the power-efficient UMC UM82C491F (or UM82C495) "Green PC" core logic chipset. It supports a broad range of x86 processors, including Intel 486SX/DX/DX2, AMD Am486, and Cyrix chips, running on Front-Side Bus speeds from 25 MHz up to 40 MHz. True to its "AIO" (All-In-One) designation, it features onboard integrated Multi-I/O controllers managing dual IDE channels, floppy drives, and standard serial/parallel ports directly on the PCB. The expansion interface provides two high-speed 32-bit VESA Local Bus (VLB) slots alongside five 16-bit ISA slots, while memory is handled by four 72-pin SIMM sockets supporting Fast Page Mode (FPM) RAM, paired with an expandable L2 secondary cache up to 512 KB of static SRAM.
The "Green PC" Focus: The UMC 491-based chipset used on the UC4915-A was part of the mid-90s industry push toward energy conservation. It featured advanced APM (Advanced Power Management) sleep modes in the BIOS, allowing the system to spin down IDE hard drives and drastically clock down the CPU frequency when left idle, a feature heavily marketed to corporate offices.
Board Layout Integration: By packing the VLB slots, the UMC logic, and the complete Multi-I/O trace routing onto a tight Baby AT form factor, ECS eliminated the reliance on secondary multi-I/O controller cards. This gave budget PC system builders a cleaner internal case layout with better airflow and fewer mechanical points of failure.