486 WB 4407 © 199? Unichip
The UNI-WB 4407 is a specialized, late-era 486 chipset design that was specifically engineered to support Write-Back (WB) L2 cache architectures. In the 486 era, the difference between "Write-Through" and "Write-Back" cache was significant; Write-Back architectures allowed the CPU to update cache memory without immediately writing to main RAM, which significantly reduced bus contention and boosted performance, especially for the high-speed 3.3V DX4 and 5x86 processors.
The "Performance" Market: While brands like SiS and UMC dominated the volume market, the uniwb4407 was often the chipset of choice for "speed-up" kits sold in the mid-90s. If a local shop was selling a "486 DX4-100 Upgrade Kit," there is a high probability it was built around this logic.