Chipset

In personal computers a chipset is a group of integrated circuits that together perform a particular function. System purchasers generally think in terms of the processor itself (such as a Pentium III, Pentium IV, or competitive chips from AMD or Cyrix). However they are really buying a system chipset that includes the microprocessor itself and often a memory cache (which may be part of the microprocessor or a separate chip—see cache) as well as the chips that control the memory bus (which connects the processor to the main memory on the motherboard.) The overall performance of the system depends not just on the processor’s architecture (including data width, instruction set, and use of instruction pipelines) but also on the type and size of the cache memory, the memory bus (RDRAM or “Rambus” and SDRAM) and the speed with which the processor can move data to and from memory.

In addition to the system chipset, other chipsets on the motherboard are used to support functions such as graphics (the AGP, or Advanced Graphics Port, for example), drive connection (EIDE controller), communication with external devices, and connections to expansion cards (the PCI bus). At the end of the 1990s, the PC marketplace had chipsets based on two competing architectures. Intel, which originally developed an architecture called Socket 7, has switched to the more complex Slot-1 architecture, which is most effective for multiprocessor operation but offers the advantage of including a separate bus for accessing the cache memory. Meanwhile, Intel’s main competitor, AMD, has enhanced the Socket 7 into “Super Socket 7” and is offering faster bus speeds. On the horizon may be completely new architecture. In choosing a system, consumers are locked into their choice because the microprocessor pin sockets used for each chipset architecture are different.