motherboard allows all the parts of your computer to receive
power and communicate with one another. Motherboards have
come a long way in the last twenty years. The first motherboards
held very few actual components. The first IBM PC motherboard
had only a processor and card slots. Users plugged components
like floppy drive controllers and memory into the slots. Today,
motherboards typically boast a wide variety of built-in features,
and they directly affect a computer's capabilities and potential
for upgrades. In this article, we'll look at the general components
of a motherboard. Then, we'll closely examine five points
that dramatically affect what a computer can do.
A motherboard by itself is useless, but a computer has to
have one to operate. The motherboard's main job is to hold
the computer's microprocessor chip and let everything else
connect to it. Everything that runs the computer or enhances
its performance is either part of the motherboard or plugs
into it via a slot or port.
shape and layout of a motherboard is called the form factor.
The form factor affects where individual components go and
the shape of the computer's case. There are several specific
form factors that most PC motherboards use so that they can
all fit in standard cases. For a comparison of form factors,
past and present, check out Motherboards.org.The form factor
is just one of the many standards that apply to motherboards.
Some of the other standards include:
socket for the microprocessor determines what kind of Central
Processing Unit (CPU) the motherboard uses.
The chipset is part of the motherboard's logic system and
is usually made of two parts -- the northbridge and the southbridge.
These two "bridges" connect the CPU to other parts
of the computer.
The Basic Input/Output System (BIOS) chip controls the most
basic functions of the computer and performs a self-test every
time you turn it on. Some systems feature dual BIOS, which
provides a backup in case one fails or in case of error during
The real time clock chip is a battery-operated chip that maintains
basic settings and the system time.
The slots and ports found on a motherboard include:
Component Interconnect (PCI)- connections for video, sound
and video capture cards, as well as network cards
Accelerated Graphics Port (AGP) - dedicated port for video
Integrated Drive Electronics (IDE) - interfaces for the hard
Universal Serial Bus or FireWire - external peripherals
Some motherboards also incorporate newer technological
Array of Independent Discs (RAID) controllers allow the computer
to recognize multiple drives as one drive.
PCI Express is a newer protocol that acts more like a network
than a bus. It can eliminate the need for other ports, including
the AGP port.
Rather than relying on plug-in cards, some motherboards have
on-board sound, networking, video or other peripheral support.
courtesy Consumer Guide Products
A Socket 754 motherboard
Many people think of the CPU as one of the most important
parts of a computer. We'll look at how it affects the rest
of the computer in the next section.
The CPU is the first thing that comes to mind when many people
think about a computer's speed and performance. The faster
the processor, the faster the computer can think. In the early
days of PC computers, all processors had the same set of pins
that would connect the CPU to the motherboard, called the
Pin Grid Array (PGA). These pins fit into a socket layout
called Socket 7. This meant that any processor would fit into
however, CPU manufacturers Intel and AMD use a variety of
PGAs, none of which fit into Socket 7. As microprocessors
advance, they need more and more pins, both to handle new
features and to provide more and more power to the chip.
socket arrangements are often named for the number of pins
in the PGA. Commonly used sockets are:
478 - for older Pentium and Celeron processors
Socket 754 - for AMD Sempron and some AMD Athlon processors
Socket 939 - for newer and faster AMD Athlon processors
Socket AM2 - for the newest AMD Athlon processors
Socket A - for older AMD Athlon processors
The newest Intel CPU does not have a PGA. It has an LGA, also
known as Socket T. LGA stands for Land Grid Array. An LGA
is different from a PGA in that the pins are actually part
of the socket, not the CPU.
who already has a specific CPU in mind should select a motherboard
based on that CPU. For example, if you want to use one of
the new multi-core chips made by Intel or AMD, you will need
to select a motherboard with the correct socket for those
chips. CPUs simply will not fit into sockets that don't match
CPU communicates with other elements of the motherboard through
a chipset. We'll look at the chipset in more detail next.
The chipset is the "glue" that connects the microprocessor
to the rest of the motherboard and therefore to the rest of
the computer. On a PC, it consists of two basic parts -- the
northbridge and the southbridge. All of the various components
of the computer communicate with the CPU through the chipset.
northbridge connects directly to the processor via the front
side bus (FSB). A memory controller is located on the northbridge,
which gives the CPU fast access to the memory. The northbridge
also connects to the AGP or PCI Express bus and to the memory
southbridge is slower than the northbridge, and information
from the CPU has to go through the northbridge before reaching
the southbridge. Other busses connect the southbridge to the
PCI bus, the USB ports and the IDE or SATA hard disk connections.
selection and CPU selection go hand in hand, because manufacturers
optimize chipsets to work with specific CPUs. The chipset
is an integrated part of the motherboard, so it cannot be
removed or upgraded. This means that not only must the motherboard's
socket fit the CPU, the motherboard's chipset must work optimally
with the CPU.