The Computer's Chipset
By Stephen Bucaro
Most people think the microprocessor is the most important component of a computer,
but much of a computer's performance is determined by the speed of its memory and
by the type and speed of it peripheral ports.
A computer's memory and peripheral ports connect through two highly integrated
chips called simply the "chipset". The chipset consists of a northbridge chip and a
The northbridge connects to the microprocessor through the Front-Side Bus (FSB).
Through the northbridge the microprocessor is connected to the systems memory
and the Accelerated Graphics Port (AGP).
The northbridge originally connected to the southbridge using the Peripheral
Component Interconnect PCI) bus, but this created a bottleneck, so newer systems
use a proprietary dedicated bus to connect to the northbridge to the southbridge.
The southbridge, sometimes called the I/O Controller Hub ICH) handles lower-speed
features like the Basic Input/Output (BIOS) chip, an integrated audio controller,
ATA and/or SATA (hard disk drive) controllers, and I/O ports like Ethernet, USB,
and expansion slots like PCI and/or PCI Express bus.
The advantage of using a chipset is that microprocessors are already highly
integrated, so to avoid stuffing more circuitry on the microprocessor chip, some of the
computers functions can be off-loaded to the chip set. Another advantage is that these
features can be operated with an independent clock, allowing the computer's owner to
experiment with overclocking (replacing the oscillator crystal with a higher frequency
crystal to try to increase performance).
However, beginning with AMD's Athlon 64-bit microprocessor and Intel's Core i series
microprocessors, the memory controller has been removed from the northbridge chip
and integrated into the microprocessor chip in order to increase performance. In today's
modern computer's, the features of the chipset have been integrated into a single chip,
like Intel's Z87 (but it's still referred to as the “chipset”).
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