AB-AX4 © 199? Abit
The AB-AX4 is one of Abit's earlier attempts to integrate the PCI bus onto a 486 platform. Unlike the refined P-series boards which were designed for maximum "tinkering" and performance, the AX4 was a more conservative, utility-focused board. It was built during a time when the PCI bus was still quite experimental for 486-class processors.
Chipset: OPTi 82C822 / 82C895 (The OPTi chipset was famous for being used in "first-generation" PCI boards before SiS and ALi took over the market).
CPU Support: Socket 3. Supports the standard 486SX, DX, DX2, and DX4 lineup.
Expansion: 2x PCI slots, 4x ISA slots, and typically 1x VLB slot (the "hybrid" bus design common in 1994).
Memory: 4x 72-pin SIMM sockets (typically restricted to FPM DRAM).
Form Factor: Baby AT.
Cache: 256KB of L2 cache (often non-upgradable, depending on the revision).
The Hybrid Bus: Many AX4 variants feature a VLB slot alongside PCI slots. This is a rare architectural in-between state. Because the VLB and PCI buses often shared the same local bus path to the CPU, you could rarely use both a high-speed VLB graphics card and a high-speed PCI disk controller simultaneously without bus contention issues.