Socket 4 Motherboards
Socket 4 was released in 1993 and was used for the initial Pentium "P5" 60MHz and 66MHz processors. Intel also released two Pentium Overdrive CPUs based on "P54C", operating at 120MHz and 133MHz. There are no other CPU options for this socket without the use of VRM adapters such as Powerleap PL-54C/MMX. Usually Socket 4 motherboards have ISA and PCI slots, though most of the earlier models have VLB or even just ISA. Socket 4 motherboards use 72-pin or 30-pin SIMM FPM DRAM modules. Most of the time they are fitted in pairs if the motherboard uses a 64-bit memory bus, however some of the earlier chipsets from OPTi were crude reworkings of their 486 chipset that still used 32-bit data paths. These motherboards allowed SIMMs to be installed one at a time, but were best avoided due to the poor performance.
All Socket 4 motherboards were made as AT motherboards or as proprietary boards for OEMs.
Chipsets
- Intel 430LX "Mercury"
- SiS 501/502/503 PCI, ISA
- ALi M1449, M1451 "Aladdin" PCI, ISA
- Forex 601A/602A PCI, VLB, ISA (PCI appears to be bridged to VLB)
- OPTi 571/572 VLB, ISA (Hybrid 486/586 design, 32-bit SRAM, DRAM)
- OPTi 693/696 VLB, EISA (supports dual CPUs)
- OPTi 596/597 "Cobra / Premium" (CPU host interface, 32bit VLB, 64bit L2 cache, 64bit DRAM)
- OPTI 546/547 "Python" (fixes bugs in the Cobra chipset, PCI and VLB not bridged)
- OPTi 556/557/558 "Viper" (supports dual CPU)
Today: Socket 4 is an uncommon choice because the boards and CPUs were produced in quantities much smaller than their 3.3V cousins, and configuration options are extremely limited. The old chipsets used for it are also drawbacks.
