Datasheet

Identifying Components of Motherboards 11
Southbridge
The Southbridge subset of the chipset, as mentioned earlier, is responsible for providing
support to the myriad onboard slower peripherals (PS/2, Parallel, IDE, and so on), manag-
ing their communications with the rest of the computer and the resources given to them.
These components do not need to keep up with the external clock of the CPU and do not
represent a bottleneck in the overall performance of the system. Any component that would
impose such a restriction on the system should eventually be developed for FSB attachment.
Most motherboards today have integrated PS/2, USB, Parallel, and Serial. Some of the
optional features handled by the Southbridge include LAN, audio, infrared, and FireWire
(IEEE 1394). When first integrated, the quality of onboard audio was marginal at best, but
the latest offerings rival external sound adapters in sound quality and number of features
(including Dolby Digital Theater Surround technology, among others).
The Southbridge is also responsible for managing communications with the other expan-
sion buses, such as PCI, USB, and legacy buses.
Figure 1.4 is a photo of the chipset of a motherboard, with the heat sink of the North-
bridge, at the top left, connected to the cover of the Southbridge, at the bottom right.
FIGURE 1.4 A modern computer chipset
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