Introduction
The motherboard or main board is the backbone of the computer. The
motherboard is the primary factor when considering how much you can
upgrade your computer. In this document we will be discussing the
common components of a motherboard and how they relate to
upgradeability. A full list of the motherboards supported by
eMachines is located in Emacinfo2 under Parts
→ Motherboards.
Much like the roads of a major city, the motherboard provides
pathways that allow various components to communicate. The
motherboard also determines the speed of those pathways, the same
way that a speed limit would control the speed of cars on the roads.
The motherboard itself is a large printed circuit board that
contains the microprocessor, the BIOS, sockets for the CPU's RAM and
a collection of slots that auxiliary cards could plug into.
If you wanted to add a floppy disk drive or a parallel port or a
joystick, you bought a separate card and plugged it into one of the
slots.
Different motherboards of different vintages typically have
different form factors. The form factor is essentially the
size, shape and design of the actual motherboard.
Why are motherboards important?
When talking about motherboards, one of the major considerations is
the motherboards upgradeability. A motherboard is typically
developed to accommodate a predefined level of technology. As
technology changes and improves, it may be required that you change
your motherboard.
CPU Upgrades
The first factor that a motherboard will determine is the
upgradeability of the Central Processing Unit (CPU). A CPU is
typically sold by its Megahertz (Millions of cycles per second)
Modern computers are now running at around 3 gigahertz (3000
Megahertz) that number can sound very impressive and fast but when
the computer sees the processor it actually will see two numbers.
The first is the Front Side Bus (FSB) speed. The FSB speed is
similar to the speed limit between the chipset or north bridge and
the CPU. The north bridge acts as a hub for all other high speed
devices such as, memory controller and CPU. The second number is the
clock multiplier. A clock multiplier is like number of people that
you can fit in a car. When you calculate the FSB multiplied by the
clock multiplier you get the CPU speed.
AMD Athlon 3200+ @ 2.0 Gigahertz = 266FSB X 7.5 Clock Multiplier
Intel Pentium 3000mhz = 400FSB X 7.5 Clock Multiplier
In both examples, you will see that if you multiply the
motherboard’s front side bus (speed limit) by the CPU’s clock
multiplier (number of people in the car) you will get processor
speed.
Memory Upgrades
One of the most cost effective ways that a consumer can increase the
performance of their computer is by the addition of more memory or
RAM. Memory is like the waiting room for the CPU. Data is read off
slower devices like the hard drive, or optical drive and stored in
memory. Memory is very fast because it has no moving parts. Memory
does not have to wait for a disk to rotate in order to read it.
Memory has instant access to all of its information.
Of course the type of memory that you can use in your computer is
determined by the motherboard. The motherboard determines two
factors that will impact your upgradeability.
RAM Type
Currently eMachines only supports two of the many different types of
memory. Each type of memory has a sub-category of the memory speed.
| Synchronous Dynamic
Random Access Memory (SDRAM) |
Double Data Rate SDRAM
(DDR) |
| • PC66 |
• PC 2100 |
| • PC100 |
• PC 2700 |
| • PC133 |
• PC 3200 |
Number of Memory Slots
The motherboard also determines how much RAM can be added to the
system by the number of memory slots and how much they can hold. An
individual memory slot has a limited size of how big a memory chip
it can hold. If a motherboard had a “maximum memory stick” limit of
512 megabytes with two memory slots the motherboards maximum memory
limit is 1024 or 512 X 2.
External Ports
A port is typically a connector that allows you to connect an
external device to your computer. The following are some of the
common ports you might find in a typical computer. Every computer is
different so you may find a computer that does not have all the
ports listed.
Musical Instrument Device Interface (MIDI)
The MIDI port typically is bundled with a sound card, its intent was
to allow the consumer to attach musical devices such as a keyboard
or synthesizer. Many manufactures also used the MIDI port for game
controllers.
The MIDI port is a 15 pin connector in a triangle shape that is
typically brown in color and located by the sound ports.
Universal Serial Bus (USB)
The USB port has taken over as the preferred connection. It gives
you a single, standardized, easy-to-use way to connect up to 127
devices to a computer. Printers, scanners, digital cameras, webcams,
modems, speakers, telephones and video phones are just a few of the
USB devices that you can find today.
USB has two factors that have contributed to its success. USB is
“Hot Swappable” which means that it is designed to be plugged in and
unplugged while the computer is turned on. Relying on the Operating
System’s Plug and Play features, USB Devices are very easy to
install and configure. The second thing that makes USB so successful
is its speed. USB 1.1 communicates at 12 Megabits Per second (*1.3
Megabytes per second) much faster than serial (9600 bits per second)
* 8 bits = 1 byte
In April 2000 USB 2.0 (High Speed USB) was introduced as an upgrade
to USB 1.1. USB 2.0 is identical looking and fully backward
compatible. USB can communicate at 1.5, 12, and 480 Megabits per
second, up to 40 times faster than USB 1.1
USB Ports are rectangular in shape they are typically not pained any
specific color because a majority of the Plug is a hole in the case.
This device has a plastic insert stopping it from being plugged in
backwards.
PS/2 Ports
PS/2 Ports were developed by IBM as a standardized smaller method of
plugging in a keyboard and mouse. Special Care should be taken
because PS/2 is Not hot swappable and unplugging a PS/2 device while
the computer is turned on may cause damage to the port.
PS/2 Ports are Circular in shape with six pins and a key. The key is
positioned in such a manor that will restrict plugging the port in
upside down or backward. The ports are colored Teal and Purple for
the Mouse and keyboard.
Caution: Some motherboards will detect if the mouse and keyboard are
switched and the computer will not turn on. If they are plugged in
to the wrong ports it will not hurt the system. Simply power off,
swap the cables to where they should be then turn back on.
Parallel Ports
The parallel port has been on most computers now for more than ten
years. The parallel port is most commonly used to connect older
printers and scanners. Most devices have converted to USB because of
its higher speed. The Parallel port is still included on new
computers for backwards compatibility.
The Parallel Port is 25 pins in a Fuchsia (Purple Red) and is about
1 ¼ inch wide.
Parallel ports have several different modes of operation. The
original parallel ports were used only for one-way communication
from the PC to the printer; newer ones include bi-directional
communication and other abilities. The normal choices for this
setting are:
• SPP: Sets the parallel port to function as a Standard
Parallel Port. This is the default (and slowest) option.
• EPP: Sets the parallel port to Enhanced Parallel Port mode.
Sometimes also called "Bi-directional"
• ECP: Sets the parallel port up as an Enhanced Capabilities
Port. This setting requires the use of a DMA channel
Serial Ports
The Serial port (Sometimes called the communications port) is about
as old as the Parallel port and was originally used to plug in
communication devices like an external modems and input devices like
a mouse. The serial port has been almost completely replaced by USB
but is still included for backward compatibility.
Serial Ports are typically nine pins but some older configurations
may have 25 pins, shaped much like a small parallel port, the Serial
port is typically painted blue.
Firewire Ports (IEEE 1394)
A subset of the SCSI-3 standard, Also called 1394, Firewire, or
i.link. Firewire was originally developed by Apple computers as a
high speed connection port. The official technical name for this
standard is IEEE 1394. The name "Firewire" is a registered trademark
of Apple Computers; Sony has named this standard I-link.
IEEE 1394 can communicate at 400 Megabits per second. Commonly used
for Digital Camcorders and networking. IEEE 1394 can support up to
64 devices per bus. Cables are twisted and can broadcast farther
than any of the other ports excluding Ethernet.
IEEE 1394 is a square with one side “pinched”. The port resembles a
taller USB port.
Super Video Graphics Adapter (SVGA)
The SVGA port is the most common port used to connect a computer
monitor. The SVGA port has 15 pins. Even though it is a 15 pin
connection rarely will a cable have all 15 pins. It is common to see
only 13 or 14 pins. Each pin is dedicated to a specific function of
the monitor. For example one pin may control the Red level, where
another pin may control vertical synchronization. If a pin is bent
or broken the rest of the image may still display without the
function of that pin.
The SVGA port is a 15 pin female connector that is typically blue in
color and shaped like a modified triangle that can only be plugged
in one way.
Internal Connectors
Internal connectors can be broken down into two categories, Headers,
and Slots. Headers are an array of Pins that project out directly
from the motherboard. Slots are connectors are plastic that a
circuit board slides into. This module we will talk about Headers,
Slots are covered in the next presentation.
Integrated Device Electronics (IDE) Header
Most motherboards have 2 IDE Headers, One for the Primary IDE
channel and one for the Secondary IDE Channel. The Headers are
typically color coded. Each IDE channel can support up to 2 devices,
a master and a slave device. Two devices on two channels allows for
a maximum of four IDE devices in the computer.
BLUE Header = Primary Channel
BLACK Header = Secondary Channel
The most common setup of an eMachines computer is as follows:
Primary Master = Hard Disk Drive
Primary Slave = Not Used
Secondary Master = Top Optical Drive
Secondary Slave = Bottom Optical Drive (Optional)
Floppy Drive Header
The floppy drive header allows the user to plug in up to two floppy
drives in the computer. It is very uncommon to see a new computer
with two floppy drives. The floppy drive header is 34 pins and
typically black in color.
USB Header
Most motherboards have USB ports that are located in the port array.
This is not very convenient for most customers that do not want to
reach behind the computer just to plug a USB device in. To address
this issue many case manufactures have started locating a number of
USB ports on the front of the case. The front USB ports connect to
the motherboard via the USB header(s). Many motherboards may have
more than one USB header. The two most common uses of the USB header
in an eMachines are Front USB port and 6 in 1 and 8 in1 media
readers.
The USB header is an array of pins arranged in two rows of five with
pin 9 missing.
|