The motherboard is the central component of a PC that connects all other major components. It contains various internal connectors for components like the CPU, memory, storage drives, graphics cards, and expansion slots. Understanding what each connector is used for helps with building and upgrading a PC. The document discusses different internal connectors on motherboards like the CPU socket, memory slots, power connectors, and various ports.

1. Understanding your Motherboard - Internal components
Understanding your motherboard is about pointing out what the bits of your motherboard actually do, if
you are not used to building or upgrading your own machine you will want to know the ins and outs of
the motherboard. The motherboard is a very important piece of equipment in your PC as it is connected
to everything. Anything of major importance is plugged straight into the board. Some things on a
motherboard are meant to be changed and altered to suit your own specifications, other things are
strictly to be left alone unless fully qualified. We will try to give you a brief bit of history if there is any on
each of these parts and some specifications.
We will start with the internal connecters and ports and then move on to the External ones. Internal
connectors are for system builders and upgrading components. These connectors are for adding
memory to the system, connecting Hard drives and optical drives as well as graphics cards and other
expansion cards.
1 - Firewire header
Firewire is also known as IEEE 1394. It is basically a high performance serial bus for digital and audio
equipment to exchange data. The technology preceded USB but yet is faster than any current USB port.
Often used for transferring digital video to the PC straight from a digital camera. The FireWire header
onboard means you can install a FireWire port on your machine. Again these cables are often supplied
as an optional extra which you will need to check with the retailer to see if they are supplied with your
board.
2 - PCI Express 16x slots
Now the most common slot for Graphics cards, the PCI Express 16x slots provides 16 separate lanes or
data transfer. PCI express 1.0 slots offer a data transfer rate of 250MB/s the second generation of PCI
express (PCI Express 2.0) offers twice the data rate at 500MB/s. Currently in development is PCI
Express 3.0 which offers 1GB/s of data transfer. PCI Express 16x slots are also the basis for both SLI
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2. and Crossfire multi graphics card setups. With the increasing demands graphics cards are putting on
systems, no less than a 16 lane slot will be good enough for any modern graphics card.
3 - PCI Express 1x Slot
Like the PCI Express 16x above the 1x slot uses exactly the same system but only has a single lane of
serial data transfer. These slots are used for expansion cards that do no require the same amount of
data transfer that a graphics card requires. You will usually find components such as tv tuners, network
cards and sound cards make use of the PCI Express 1x slot. You will also notice the difference in size
between the 1x and the 16x slots. The PCI Express 1x slot is noticeably smaller and easy to spot.
4 - Chipset - North Bridge (with heatsink)
The Motherboards chipset can be described as what sets it apart from other boards in its category.
Different chipsets contain different features and components. A chipset is a number of integrated
circuits built onto the board to provide specific functions e.g. one part of the chipset may be an onboard
component such as a modem or sound chip. Other parts may be used to control the CPU functions.
Most chipsets are designed to work with only one "class" of CPU although now many older chipsets
support more than one type of CPU such as socket 7 which supports the Pentium, Cyrix 686, Cyrix MII,
AMD K6 and K6-2. There are certain restrictions though to what type of processor a chipset can handle
because of the logic that the CPU uses to access the memory and its cache etc. Since these chips are
working harder with each generation, motherboard manufacturers have started to put heatsinks and
active coolers (fans) on the main parts of the chipset to disperse some of the heat. For more information
on chipsets see our What does a chipset do article.
5 and 8 - ATX Power connector
The standard ATX power connector, the cable for this will be coming from the PSU, a clip is normally
provided to make sure you get them in the correct order. As a tip, don't try to push too hard if its stuck,
check to see that it is in the correct way, I have seen plenty of power connectors where the pins have
pushed out some of the connectors, these can be difficult to get back into place, so its best to be
careful.
6 - CPU (Central Processing Unit) socket
All the CPU "sockets look very similar, however they are different in the way they have different amount
of pins and in different layouts. There are currently two major CPU socket types PGA and LGA. PGA or
Pin Grad Array uses a system of pins on the CPU and holes on the socket to line up and hold a CPU in
place. The introduction of the ZIF (Zero Insertion Force) socket for PGA types allowed the CPU's to be
lined up without any pressure on the CPU until a level is pulled down. LGA or Land Grid Array uses a
system of gold plated copper pads that make contact with the motherboard. It is very important to read
your motherboard manual to discover what types of CPU's you motherboard supports as most
motherboards are aimed at a specific type of CPU.
7 - DIMM (Double Inline Memory Module) slots
DIMM's are by far and away the most used memory types in today's computers. They vary in speeds
and standards however and they need to match up to what your motherboard has been designed to
take. The four standards of DIMM's being used at the moment are SDR (Single Data Rate), DDR
(Double Data Rate), DDR2 and DDR3. The speeds of memory can vary between 66Mhz to 1600Mhz.
9 - Motherboard controls

3. Not available on all motherboards, but some allow direct control of the motherboard via simple buttons.
Power switch, error checking, CMOS clearing, passwords and more features can be accessed directly
on the motherboard on some models.
10 - Chipset - South Bridge
When we talk about chipsets you mainly only ever hear about the North bridge. Even those into PC
technology have a hard time naming the south bridges without looking them up. Names like Nforce 2
and KT600 are North bridges. The South Bridge does an important job as well. It handles things like the
PCI bus, onboard Network and sound chips as well as the IDE and S-ATA buses.
11 - Serial ATA Connector
Serial ATA or more commonly seen as S-ATA is a new way of connecting your Hard Drives to your PC.
S-ATA drives have the capability of being faster than the IDE counterparts and also have smaller
thinner cables which help with the airflow of the system. S-ATA hard disks are fast becoming the norm
for hard drive technology. Current motherboards feature both IDE and S-ATA connectors to facilitate all
types of storage hardware.
12 - USB 2.0 header
As well as having USB ports on the rear of the motherboard, motherboard manufacturers often add a
couple of USB headers so you can connect optional cables for extra USB ports. These cables are often
supplied and you only need to add them on if you need the extra connectivity. USB 2.0 replaced USB
1.1 as a much faster solution. It is backwards compatible meaning all USB 1.1 devices will work in these
new USB 2.0 ports.
13 - Motherboard Battery
The battery gives the board a small amount of power in order to store some vital data on your machine
when the power is off. Data stored is that like the time and date so you don't have to reset them every
time you boot the machine up. Motherboard batteries are usually long lasting Lithium batteries.
Removing this can reset all the data on your machine including the BIOS settings, however not
replacing this correctly can lead to irreparable damage to the motherboard. Only remove the battery if it
is dead or if you can't have access any other way to resetting the data on your machine by use of the
clear CMOS jumper or something similar.
14 - PCI (Peripheral Component Interconnect) slot
The PCI bus (not PCI express) is now an older technology and although the PCI slots are still available,
they have decreased in number and are being replaced by the PCI Express 1x slots. Its unlikely that
you will get a motherboard without a PCI slot at the moment due to the fact that a lot of components still
use the standard PCI slot. It would be awkward to upgrade to a system without PCI slots as it may
mean upgrading more components than you would like to,
15 - Floppy Drive Connector
More simple than the IDE connector you only have to remember to get the red line to pin 1 of the
connector and the red line to pin 1 on the floppy drive, This port is only to be used with floppy
drives. You may not have a floppy controller on your motherboard as its slowly being phased out as
more people are using writable CD's and DVDs to transfer data, to store data and to use as boot up
discs.

4. 16 - IDE connector Not on Diagram
The connector to which you will insert an IDE cable (supplied with motherboard) IDE cables connect
devices such as hard disks, CD Drives and DVD Drives. The current 4 standards of IDE devices are
ATA 33/66/100 and 133. the numbers specify the amount of data in Mb/s in a max burst situation. In
reality there is not much chance of getting a sustain data rate of this magnitude. Both the connectors
and devices are backwards compatible with each other, however they will only run at the slowest rated
speed between them. All IDE cables will come with a red line down one side, this red line is to show
which way it should be plugged in. The red line should always connect to pin one of the IDE port.
Checking your motherboard documentation should show you which end is pin one. In some cases it will
be written on the board itself.
In the case of ATA 66/100/133 there is a certain order that you plug devices in, the cable is colour
coded to help you get them in the correct order.
 The Blue connector should be connected to the system board
 The Black connector should be connected to the master device
 The Grey Connector should be connected to the slave device
17 - BIOS (Basic Input Output System) Chip - Not on Diagram
The BIOS holds the most important data for your machine, if configured incorrectly it could cause your
computer not to boot correctly or not at all. The BIOS also informs the PC what the motherboard
supports in terms off CPU etc. This is why when a new CPU is introduced that physically fits into a slot
or socket you may need a BIOS update to support it. The main reason for this is that different CPU's
use different logics and methods and so the BIOS has to understand certain instructions from the CPU
to recognize it.
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1. Other memories
Last time we showed how to build arbitrarily-large static memories from single-bit RAM cells.
Today we’ll look at some other kinds of memories.
– Dynamic RAM is used for the bulk of computer memory.
– Read-only memories and PLAs are two “programmable logic devices,” which can
be considered as special types of memories.
2. Types of memories
• There are two main kinds of random access memory.
– Static RAM costs more, but the memory is faster. Static RAM is often used to
implement cache memories. It is volatile.
– Dynamic RAM costs less and requires less physical space, making it ideal for
larger-capacity memories. However, access times are also slower. It is volatile.
ROMs and PLAs are read-only memory. They are non-volatile. They contain programs such as
system BIOS.

5. 3. Dynamic memory in a nutshell
 Dynamic memory is built with capacitors.
a. A stored charge on the capacitor represents a logical 1.
b. No charge represents a logic 0.
 However, capacitors lose their charge after a few milliseconds. The memory
requires constant refreshing to recharge the capacitors. (That’s what’s
“dynamic” about it.)
 Dynamic RAMs tend to be physically smaller than static RAMs.
– A single bit of data can be stored with just one capacitor and one
transistor, while static RAM cells typically require 4-6 transistors.
– This means dynamic RAM is cheaper and denser—more bits can be
stored in the same physical area.
4. SDRAM
 Synchronous DRAM, or SDRAM, is one of the most common types of PC memory
now.
 Memory chips are organized into “modules” that are connected to the CPU via a
64-bit (8-byte) bus.
 Speeds are rated in megahertz: PC66, PC100 and PC133 memory run at 66MHz,
100MHz and 133MHz respectively.
 The memory bandwidth can be computed by multiplying the number of transfers
per second by the size of each transfer.
– PC100 can transfer up to 800MB per second (100MHz x 8 bytes/cycle).
– PC133 can get over 1 GB per second.
5. DDR-RAM
 A newer type of memory is Double Data Rate, or DDR-RAM.
 It’s very similar to regular SDRAM, except data can be transferred on both the
positive and negative clock edges. For 100-133MHz buses, the effective memory
speeds appear to be 200-266MHz.
 This memory is confusingly called PC1600 and PC2100 RAM, because
– 200MHz x 8 bytes/cycle = 1600MB/s
– 266MHz x 8 bytes/cycle = 2100MB/s.
 DDR-RAM has lower power consumption, using 2.5V instead of 3.3V like SDRAM.
This makes it good for notebooks and other mobile devices.
6. RDRAM
 Another new type of memory called RDRAM is used in the Playstation 2 as well
as some Pentium 4 computers.
 The data bus is only 16 bits wide.
 But the memory runs at 400MHz, and data can be transferred on both the
positive and negative clock edges.
– That works out to a maximum transfer rate of 1.6GB per second.
– You can also implement two “channels” of memory, resulting in up to 3.2GB/s of
bandwidth.
7. Dynamic vs. static memory

6.  In practice, dynamic RAM is used for a computer’s main memory, since it’s cheap
and you can pack a lot of storage into a small space.
– These days you can buy 1GB of memory for as little as $50-60.
– You can also load a system with 4GB or more of memory.
 The disadvantage of dynamic RAM is its speed.
– Transfer rates are 800MHz at best, which can be much slower than the processor
itself.
– You also have to consider latency, or the time it takes data to travel from RAM to
the processor.
 Real systems augment dynamic memory with small but fast sections of static
memory called caches.
a. Typical processor caches range in size from 512KB to 1024KB.
b. That’s small compared to a 1GB main memory, but it’s enough to significantly
increase a computer’s overall speed.
c. You’ll study caches later on in CS232.
8. Read-only memory
 A read-only memory, or ROM, is a special kind of memory whose contents
cannot be easily modified.
– The WR and DATA inputs that we saw in RAMs are not needed.
– Data is stored onto a ROM chip using special hardware tools.
 ROMs are useful for holding data that never changes.
– Arithmetic circuits might use tables to speed up computations of logarithms or
divisions.
– Many computers use a ROMto store important programs that should not be
modified, such as the system BIOS.
– PDAs, game machines, cell phones, vending machines and other electronic
devices may also contain non-modifiable programs.
9. Memories and functions
 ROMs are actually combinational devices, not sequential ones!
– You can’t store arbitrary data into a ROM, so the same address will always
contain the same data.
– You can think of a ROMas a combinational circuit that takes an address as input,
and produces some data as the output.
 A ROMtable is basically just a truth table.
– The table shows what data is stored at each ROM address.
– You can generate that data combinationally, using the address as the input.
10. Decoders

7.  We can already convert truth tables to circuits easily, with decoders.
 For example, you can think of this old circuit as a memory that “stores” the sum and
carry outputs from the truth table on the right.
11. ROM setup
 ROMs are based on this decoder implementation of functions.
a. A blank ROM just provides a decoder and several OR gates.
b. The connections between the decoder and the OR gates are “programmable,” so
different functions can be implemented.
 To program a ROM, you just make the desired connections between the decoder
outputs and the OR gate inputs.
12. ROM example
 Here are three functions, V2V1V0, implemented with an 8 x 3 ROM.
 Blue crosses (X) indicate connections between decoder outputs and OR gates.
Otherwise there is no connection.
13. The same example again
 Here is an alternative presentation of the same 8 x 3 ROM, using “abbreviated”
OR gates to make the diagram neater.
14. Why is this a “memory”?
15. This combinational circuit can be considered a read-only memory.
a. It stores eight words of data, each consisting of three bits.
b. The decoder inputs form an address, which refers to one of the eight available
words.
c. So every input combination corresponds to an address, which is “read” to
produce a 3-bit data output.
16. ROMs vs. RAMs
 There are some important differences between ROM and RAM.
– ROMs are “non-volatile”—data is preserved even without power. On the other
hand, RAM contents disappear once power is lost.
TERMS
Cable Modem
A cable modem is a peripheral device used to connect to the Internet. It operates over coax cable
TV lines and provides high-speed Internet access. Since cable modems offer an always-on
connection and fast data transfer rates, they are considered broadband devices.

8. Dial-up modems, which were popular in the early years of the Internet, offered speeds close to
56 Kbps over analog telephone lines. Eventually, DSL and cable modems replaced dial-up
modems since they offered much faster speeds.
CD-ROM
Stands for "Compact Disc Read-Only Memory." A CD-ROM is a CD that can be read by a
computer with an optical drive. The "ROM" part of the term means the data on the disc is "read-
only," or cannot be altered or erased. Because of this feature and their large capacity, CD-ROMs
are a great media format for retail software.
Hard Drive
The hard drive is what stores all your data. It houses the hard disk, where all your files and
folders are physically located.
USB
Stands for "Universal Serial Bus." USB is the most common type of computer port used in
today's computers. It can be used to connect keyboards, mice, game controllers, printers,
scanners, digital cameras, and removable media drives, just to name a few.
Download
Download can be used as either a verb or a noun. As a verb, it refers to the process of receiving
data over the Internet.
Troubleshooting
Troubleshooting is the process of diagnosing the source of a problem. It is used to fix problems
with hardware, software, and many other products. The basic theory of troubleshooting is that
you start with the most general (and often most obvious) possible problems, and then narrow it
down to more specific issues.
Networking terms
1. An access point (AP) is a special-purpose communication device on a wireless local area
network (WLAN). Access points act as a central transmitter and receiver of WLAN radio
signals.
2. In computer networking, ad hoc mode refers to the ability of wireless devices to
communicate directly with each other. Ad hoc wireless networks are used for peer-to-
peer communication when central access points or wireless routers are not available.
3. A network adapter provides the interface between a computer and a network connection.
The term network adapter was popularized originally by Ethernet add-in cards for PCs.
4. An aircard is a type of wireless adapter used for connecting to cellular networks. Several
different forms of aircards are available together with service plans from phone providers
like Verizon and AT&T.

9. 5. A proxy server acts an intermediate gateway between you and your Internet connection.
These servers can improve both your network performance and also your online privacy.
6. Application Programming Interfaces (APIs) provide controlled access to software
libraries and modules. Networking APIs like WinSock are entry points to libraries that
implement network communication protocols.
7. An Application Service Provider (ASP) is an business that offers software services to
customers, using computer networks and the Internet as the mechanism to distribute and
manage the service.
8. In computer networking, a backbone is a central conduit designed to transfer network
traffic at high speeds. Backbones typically consist of network routers and switches
connected by fiber optic or Ethernet cables.
9. BitTorrent is a leading P2P network system for download of music, movies and software
files. The BitTorrent network protocol is designed to support large numbers of
simultaenous uploads and downloads over the Internet.
10. Definition: Bluetooth (sometimes Blue Tooth) is a low cost, short range, low power-
consuming wireless networking technology commonly used in cell phones and other
portable devices. Bluetooth technology also supports the networking of peripherals such
as printers and keyboards.
11. A fiber optic cable is a network cable made from strands of glass fibers. Fiber optic
cables carry signals using pulses of light. These cables are designed for long distance
network communications, although fiber to the home installations are becoming more
common.
12. In computer networking, hacking is any technical effort to manipulate the normal
behavior of network connections and connected systems. Historically, hacking referred to
constructive, clever technical work that was not necessarily related to computer systems.
Today, however, hacking and hackers are most commonly associated with malicious
programming attacks on the Internet and other networks.
13. (A definition.) High-speed Digital Subscriber Line (HDSL) is an implementation of DSL
that uses multiple phone lines.
14. The term hosting refers to a site or service that maintains files on behalf of clients.
Besides Web hosting services, other types of network file hosting services are common
including FTP sites and shared network folders on a PC.
15. A hot spot (usually "hotspot") is a public location where Wi-Fi Internet access can be
obtained. Hot spots are increasingly found in airports, hotels, coffee shops, and other
places where business people tend to congregate.

10. 1. WHITE& ORANGE
2. ORANGE
3. WHITE& GREEN
4. BLUE
5. WHITE& BLUE
6. GREEN
7. WHITE& BROWN
8. BROWN
1. WHITE& GREEN
2. GREEN
3. WHITE& ORANGE
4. BLUE
5. WHITE& BLUE
6. ORANGE
7. WHITE& BROWN
8. BROWN