PC Hardware in a Nutshell, 3rd Edition

Processor Support

Motherboards are designed to accept a particular processor (CPU) or CPU family. Which CPUs a motherboard supports is determined by the following:

Chipset

Determines the CPU types the motherboard accepts. Non-Intel chipsets typically support a wide range of Intel and compatible CPUs. Officially, Intel chipsets support only Intel CPUs. In fact, compatible CPUs such as the AMD K5/K6/K6-2, the Cyrix/IBM 6x86 (M1) and 6x86MX (M2), and the IDT WinChip run fine in motherboards with the appropriate Intel chipset. Also, although recent compatible CPUs can be installed in motherboards with older chipsets, those CPUs may not provide the highest performance of which they are capable, and some advanced features may not be supported by the chipset. The chipset also determines the fastest CPU that the motherboard can support. Intermediate speeds may or may not be supported, depending on the configuration options available for the motherboard.

CPU voltages supplied

Early Pentium-class CPUs use 5 volts. Later ones use 3.3 volts or 2.8 volts, and most later Pentium-class CPUs use dual voltage, running the internal core logic at a lower voltage than the CPU components that interface with cache, main memory, and other external components. Early fifth-generation motherboards supplied a fixed voltage to the CPU. Later ones included a Voltage Regulator Module (VRM) that allowed the motherboard to be configured to supply different voltages, according to the requirements of the CPU installed. ...