AB-PM4 © 199? Abit
The AB-PM4 was positioned as a high-performance alternative to the SiS and ALi boards. By utilizing the UMC chipset, Abit aimed to provide users with a board that could squeeze out extra performance in memory-intensive DOS applications. It is widely considered one of the most "optimized" 486 motherboards ever produced.
Chipset: UMC UM8498F / UM8496F.
CPU Support: Socket 3. Like the other Abit "P" boards, it is highly jumper-configurable for voltages and multipliers, supporting Intel, AMD, and Cyrix 486-class chips.
Expansion: 3x PCI slots / 4x ISA slots.
Memory: 4x 72-pin SIMM sockets.
Form Factor: Baby AT.
Cache: 256KB or 512KB of L2 cache.
The UMC Speed Demon: The UMC UM8498 chipset implemented on the AB-PM4 is frequently benchmarked as faster than the SiS 496/497 in terms of DRAM latency. If you wanted the highest possible frame rates in DOOM or Duke Nukem 3D on a 486, this was often the board that achieved it.
The "P" Series Distinction: Having the PB4 (ALi), PV4 (SiS), and PM4 (UMC) gives your database a perfect look at the "Chipset Wars" of the mid-90s. Abit was essentially letting the customer choose their preferred chipset while keeping the same high-quality PCB design and excellent documentation.