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TECH TALK
By KCnet Tech - Roxanne Fryer
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Thanks to "How Stuff Works" for the information
used in this week's tip.
If you've ever taken the case off of a computer,
you've seen the one piece of equipment that ties everything together --
the motherboard. A motherboard allows all the parts of your computer to
receive power and communicate with one another.
| 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. |
A modern motherboard
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The 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:
• The 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 updating.
• 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:
• Peripheral Component Interconnect (PCI)-
connections for video, sound and video capture cards, as well as network
cards
• Accelerated Graphics Port (AGP) - dedicated
port for video cards.
• Integrated Drive Electronics (IDE) - interfaces
for the hard drives
• Universal Serial Bus or FireWire - external
peripherals
• Memory slots
Some motherboards also incorporate newer technological
advances:
• Redundant 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.
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.
Sockets and CPUs
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 any motherboard.
Today, 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.
Current socket arrangements are often named
for the number of pins in the PGA. Commonly used sockets are:
• Socket 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.
Anyone 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 their PGA.
The CPU communicates with other elements of
the motherboard through a chipset. We'll look at the chipset in more detail
next.
Chipsets
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.
The northbridge connects directly to the processor
via the front side bus (FSB). A memory. The northbridge also connects to
the AGP or PCI Express bus and to the memory itself.
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The northbridge and southbridge
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The 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.
Chipset 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.
Next, we'll look at busses, which, like the
chipset, carry information from place to place.
Bus Speed
A bus is simply a circuit that connects one
part of the motherboard to another. The more data a bus can handle at one
time, the faster it allows information to travel. The speed of the bus,
measured in megahertz (MHz), refers to how much data can move across the
bus simultaneously
The 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.
Chipset 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.
Next, we'll look at busses, which, like the
chipset, carry information from place to place.
Bus Speed
A bus is simply a circuit that connects one
part of the motherboard to another. The more data a bus can handle at one
time, the faster it allows information to travel. The speed of the bus,
measured in megahertz (MHz), refers to how much data can move across the
bus simultaneously.
Busses connect different parts of the motherboard
to one another
Bus speed usually refers to the speed of the
front side bus (FSB), which connects the CPU to the northbridge. FSB speeds
can range from 66 MHz to over 800 MHz. Since the CPU reaches the memory
controller though the northbridge, FSB speed can dramatically affect a
computer's performance.
Here are some of the other busses found on
a motherboard:
• The back side bus connects the CPU with
the level 2 (L2) cache, also known as secondary or external cache. The
processor determines the speed of the back side bus.
• The memory bus connects the northbridge
to the memory.
• The IDE or ATA bus connects the southbridge
to the disk drives.
• The AGP bus connects the video card to the
memory and the CPU. The speed of the AGP bus is usually 66 MHz.
• The PCI bus connects PCI slots to the southbridge.
On most systems, the speed of the PCI bus is 33 MHz. Also compatible with
PCI is PCI Express, which is much faster than PCI but is still compatible
with current software and operating systems. PCI Express is likely to replace
both PCI and AGP busses.
The faster a computer's bus speed, the faster
it will operate -- to a point. A fast bus speed cannot make up for a slow
processor or chipset.
Now let's look at memory and how it affects
the motherboard's speed.
Memory and Other Features
We've established that the speed of the processor
itself controls how quickly a computer thinks. The speed of the chipset
and busses controls how quickly it can communicate with other parts of
the computer. The speed of the RAM connection directly controls how fast
the computer can access instructions and data, and therefore has a big
effect on system performance. A fast processor with slow RAM is going nowhere.
The amount of memory available also controls
how much data the computer can have readily available. RAM makes up the
bulk of a computer's memory. The general rule of thumb is the more RAM
the computer has, the better.
A motherboard's memory slots directly affect
what kind and how much memory is supported. Just like other components,
the memory plugs into the slot via a series of pins. The memory module
must have the right number of pins to fit into the slot on the motherboard.
In the earliest days of motherboards, virtually
everything other than the processor came on a card that plugged into the
board. Now, motherboards feature a variety of onboard accessories such
as LAN support, video, sound support and RAID controllers.
Motherboards with all the bells and whistles
are convenient and simple to install. There are motherboards that have
everything you need to create a complete computer -- all you do is stick
the motherboard in a case and add a hard disk, a CD drive and a power supply.
You have a completely operational computer on a single board.
For many average users, these built-in features
provide ample support for video and sound. For avid gamers and people who
do high-intensity graphic or computer-aided design (CAD) work, however,
separate video cards provide much better performance.
~ Thanks to How Stuff Works ~
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