486 motherboard using the OPTi OPTi 82C392, 82C493 chipset © 199? Unknown
This chipset was a high-performance "Single-Chip" system controller (the 82C493) paired with a robust data buffer (the 82C392). It was designed specifically to provide full PCI 2.0 compliance for the 486 platform. It was highly favored by manufacturers who wanted to build boards that could compete with the ALi-based systems in terms of throughput, but with the added flexibility of OPTi's well-documented BIOS registers.
Processor Support: Optimized for the full 486 lineup: Intel 486DX, DX2, DX4, and the high-performance AMD 5x86 (up to 133MHz).
Bus Architecture: True PCI/ISA/VLB potential. Most boards using this chipset (like the famous PCCHIPS M919 or various Abit models) were true "hybrid" boards, allowing for a bridge between older VLB peripherals and new PCI cards.
Memory: Typically supported up to 128MB or 256MB of RAM using 72-pin SIMMs, often with advanced support for parity-checked memory—a holdover from the professional workstation requirements of the era.
Cache: Features advanced Write-Back L2 cache support, which was essential for keeping the 486DX4 and 5x86 processors fed with data.
The Hybrid King: The op82c392 is arguably one of the most common chipsets found on "multimedia upgrade" motherboards from 1994–1995. Because it could handle VLB and PCI simultaneously, it was the preferred choice for users who wanted to keep their VLB graphics card but add a PCI sound card or a PCI IDE controller.