In a personal computer, the integrated circuit (IC) chips that define the functions of a CPU. The chipset is in charge of controlling the flow of instructions to the CPU as well as defining the available buses. Chipsets are normally integrated – soldered onto the motherboard.
On early personal computers these functions required as many as 30 individual chips. Current PCs have consolidated all these circuits into only two or three chips.
Intel (Pentium) and AMD-based computers have two distinctive chips. The northbridge typically handles communications between the CPU, RAM, and AGP or PCI Extended graphics cards. Some northbridge chips also contain integrated video controllers. The southbridge chip normally defines and controls the operation of other buses and devices, including the PCI bus, the PS/2 interface for keyboard and mouse, the serial port, the parallel port, and the floppy drive controller.
The chipset used by a given manufacturer of motherboards can have a significant impact on the way in which that board (and the resulting computer that uses it) will interact with various peripheral devices. Some hardware, particularly more exotic audio recording hardware, can be pretty picky about chipsets and their associated data protocols.