Introduction :

Motherboard is the most important component of the system. It is the Printed Circuit Board (PCB) where all the components of the system are connected. The Central Processing Unit (CPU), memory, hard drive and every other part of the system is connected to the motherboard by means of socket, slots and connectors. Generally a motherboard chipset controls the features and abilities of the motherboard. The motherboard chipset is a series of chips that are part of the motherboard. The chipset is very important for the operation of the system.

1. Types of Motherboards

Motherboards, the capacity and efficiency of motherboards differ according to the type of system you use. Motherboards are classified depending on the devices they support:

  • Integrated
  • Non-integrated 

Motherboards which have all the ports for connecting various devices on board are known as Integrated motherboards. All the latest desktop, server and laptop boards are of the integrated type. Motherboards which do not support connecting devices are known as Non-integrated motherboards. Older desktop and server motherboards were of non integrated types.

Otherwise motherboards are classified on the basis where it is used:

  • Desktop Motherboard
  • Server Motherboard
  • Laptop Motherboard


Desktop Motherboards

Desktop motherboards are used in personal or desktop computers. As it is used for applications at home and in office, this type of motherboard is the most basic type. 

Server Motherboards

Server motherboards are more advanced than desktop motherboards and are designed to offer high-end services which are more reliable and ready to operate in 24*7 environments. These motherboards support expansion and future upgrades and can handle major applications. Server motherboards also offer multiple sockets, slots and connectors as compared to desktop motherboards to support more number of devices for redundancy.

Laptop Motherboards

Laptop motherboard is used to connect different parts of a laptop system. These motherboards generally have very advanced features as compared to the desktop motherboards and most of the functions have been integrated into the laptop motherboards.

2. Manufacturers of Motherboard

Motherboards are available in various sizes and configurations. Some motherboards support 32 and 64 bit processor as well as operating systems. It is manufactured by many companies such as Asus, Intel, MSI and Gigabyte. Every company manufactures boards with certain standard configuration. These motherboards support only certain types of peripheral devices configuration. The boards manufactured by the various companies are mentioned below.

Asus Motherboards

Asus Tek Incorporation develops many products such as motherboards, graphic cards, networking support, notebooks and wireless networking support. Asus manufactures motherboards that support different types of processors such as Intel and AMD. The motherboards manufactured by Asus support 64 bit computing technology.
Intel Motherboards

Intel manufactures processors, motherboards and graphic cards. Intel motherboards are available in various configurations and different form factors. Motherboards are available in two types namely desktop and server boards.
MSI motherboard

MSI is well known for its high performance designs and cutting edge products. From the begining, MSI has had prided in delivering some of the most high performance products in the market by providing unique designs and performance driven technological innovation.
Gigabyte Motherboards

Gigabyte Technology manufactures motherboards, graphic cards, other peripheral devices, networking devices, computers and other home equipments. Gigabyte manufactures motherboards that are available for different types of processors such as Intel and AMD. The newer versions of the board support the latest processors such as the core processors and the 64 bit processors.
3. Chipsets

Chipset is a group of Integrated Circuits (IC) Generally a motherboard chipset controls the features and abilities of the motherboard Chipsets provide interface for the devices such as the CPU, memory and I/O devices. The chipset controls the data transfer between every component of the system. Previously, a single chip or multiple chips performed every function of the chipset Over time, all these chips were integrated to form the chipset that controlled system operations A modern chipset consists of the Northbridge and the Southbridge. These two microchips determine the features and capabilities of a motherboard. The Northbridge handles data communication between the CPU and memory, The Southbridge handles data from the PCI. Hard disks and other devices that are not under the control of the Northbridge. 64 bit computing technology chipsets are also available today. 

Different chipset manufacturers are such as the Nvidia, Intel, AMD. VIA and SIS/The Intel G41, P45, H55 and the X5B chipsets are the most common chipsets available today. 64 bit computing technology chipsets are also available today. Figure 3.5 shows the advanced chipset organization.

Intel-Bridge Architecture

When the bridge concept started, the communication between the north bridge and the south bridge was done through the PCL bus. The bandwidth available for the PCI bus is 132 MB/s and is shared between all PCI devices in the system.

But when high-end video cards (at that time, the video cards were PCI) and high performance hard disk drives were launched, a bottleneck situation arouse. Modem ATA/133 hard disk drives, has the same transfer rate of the PCI bus so an ATA/133 hard drive would occupy the entire bandwidth, slowing down the communication speed of all devices connected to the PCI bus. For the high-end video cards, a new bus is connected directly to the north bridge, called AGP (Accelerated Graphics Port) was designed. 

When Intel started using this architecture it started calling the bridges as “hubEvery chipset supports a CPU interface. The CPU interface can be Socket LGA775, 1156 or 1366. So the chipset that you choose must support the interface required by your CPU. You must choose the appropriate chipset depending on your needs.s”, the north bridge became MCH (Memory Controller Hub) and the south bridge became ICH (1/O Controller Hub). When the CPU reads data from a hard drive, the data is transferred from the hard drive to the south bridge, then to the north bridge using the dedicated bus and then to the CPU. The speed of this dedicated bus depends on the chipset model. For example, on Intel 925X chipset this bus has a maximum transfer speed of 2 GB/s. Also, the manufacturers call this bus as DMI (Direct Media Interface) or Intel Hub Architecture.

The new DX58SO motherboard platform as shown in figure 3.5 consists of the Intel Core i7 processor (CPU), Intel X58 Express Chipset (IOH) and the ICH. The CPU now incorporates the system memory controller and accesses DDR3 memory through three independent memory channels. The IOH provides support for the two PCle graphics slots and connects to the CPU via the Quick Path Interconnect (QPI) bus The ICH provides the support for the SATA, USB and other system interfaces and is connected to the IOH via the DMI bus Every chipset supports a CPU interface. The CPU interface can be Socket LGA775, 1156 or 1366. So the chipset that you choose must support the interface required by your CPU. You must choose the appropriate chipset depending on your needs.

Every chipset supports a CPU interface. The CPU interface can be Socket LGA775, 1156 or 1366. So the chipset that you choose must support the interface required by your CPU. You must choose the appropriate chipset depending on your needs.

South Bridge or IO Controller Hub (ICH)

south bridge, the ICH is used to connect and control peripheral devices. You can find different ICH version in Appendix

Intel Chipsets

Intel is the leading manufacturer of chipsets worldwide. You can choose from a wide range of Intel chipsets for your system. Table 3.6 lists some of the Intel Chipsets with their characteristics.
AMD Chipsets

AMD manufactures a wide variety of chipsets that are very popular.
4. Recognizing your Motherboard

You can recognize your motherboard by checking the model number. Mostly mode number of a motherboard is written near the processor or in between PCI slots in case of older motherboards. Figure 3.6 shows model and socket number of a motherboard.

Chipset number of the motherboard can be derived from the model number. In this case model number of the motherboard is D915GAV/D915PGN and

Chipset number is 915

Also you can see the socket number as mentioned in the figure i.e. LGA775. For indenting any motherboard if it is faulty you have to provide model number, chipset number and socket number of a motherboard.

5. Components of a Motherboard

Motherboard contains sockets, slots and connectors for connecting various devices. contains socket for attaching the microprocessor and slots for attaching RAM, graphic cards and any other device. It contains a super I/O chip for connecting slower devices to the processor and PCI bus slots for connecting various peripheral devices. A CMOS battery is mounted on the motherboard to keep the system updated with latest date and time. An on-board CPU voltage regulator is provided to regulate power supply to the processor. You can configure the motherboard using jumpers.

Onboard Components
  • The onboard components of the motherboard are:
  • Processor Socket (1) – Connects the processor to motherboard.
  • Northbridge (2)-Handles the communication between the CPU, main memory, AGP Port and another very important component known as the south bridge controller.
  • Southbridge (3) – Handles all the operations of devices and buses that are not controlled by the north bridge.
  • Memory Slots (4) – Connects the RAM modules to motherboard.
  • Super I/O controller (5)- Controls low speed I/O devices like mouse, keyboard and serial port.
  • Flash ROM (6) – Contains a programmable BIOS.
  • Standby Power LED (7)- Indicates if there is standby power on the motherboard.
  • Audio CODEC (8) – Enables audio playback by providing DAC channels.
  • LAN controller (9) – Supports networking functions.
  • Mouse port (10) – Connects the PS/2 mouse.
  • Parallel port (11)-Connects parallel devices like printers.
  • RJ-45 port (12) – Enables connection of LAN through a switch.
  • Line In jack (13) – Connects audio devices like a tape player.
  • Line Out jack (14)- Connects a speaker or a headphone.
  • Microphone jack (15) – Connects a microphone.
  • USB ports (16) – Enables connection to USB devices.
  • Video port (17) – Used to connect to a VGA monitor or another VGA compatible device:
  • Serial port (18)- Connects the modem or other serial devices.
  • Keyboard port (19)- Connects the PS/2 keyboard.
CPU Socket

CPU socket is an interface that connects the CPU with motherboard. Different types of sockets are used for different types of processors. It consists of holes in which the pins of the processor are installed. Sockets are already installed on the board. Now days most of the sockets used are built on the Land Grid Array (LGA) architecture where pins are available on sockets. Pin less processors are placed onto the socket without exerting any pressure. The sockets vary in size and pin count.

Memory Slots

Memory slots provide an interface for attaching RAM on the board. RAM module is inserted in these slots. Most of the motherboards come equipped with at least 2 memory slots The maximum number of slots available depends on the motherboard. Most Memory slots are Double Inline Memory Module (DIMM) type.

Super I/O Chip

Super I/O chip is a single chip which controls slower I/O devices which are not controlled by south bridge. It controls the Floppy drive, serial ports, PS/2 mouse, some keyboard functions, fans and parallel ports. All the latest motherboards come with a super I/O controller chip.


Basic Input Output System (BIOS) contains all necessary programs required to operate the basic system utilities such as the display device, keyboard or disk drives. It is a software that is built into the Read Only Memory (ROM) of the computer. BIOS provide the basic input output functionality of the system. BIOS are available even when none of the disk drives work. It also controls the configuration of the various devices and runs a test to check whether all the devices are properly working when the computer is started. This test is called the Power On Self Test (POST). 

CMOS Battery

Complementary Metal Oxide Semiconductor (CMOS) battery provides power to the CMOS chip of the motherboard. The CMOS chip stores the time and settings of the system. The CMOS chip saves the settings and time when the computer is switched off with the help of the battery power. The life of the battery is around 5 years but it depends mainly on the environment in which it is used. CMOS batteries are made up of Lithium and operate at 3 volts. Figure 3.10 shows a CMOS battery.

Specification of CMOS battery:


Rating-3 Volt DC

Expansion Slots

Expansion slots on a motherboard enable you to connect expansion cards to the motherboard. The motherboard shown in the figure 3.11 has three PCI slots where you can connect expansion/PCI cards. The different PCI cards include LAN card, graphics card, and SCSI card. The cards must comply with PCI specifications. The PC) cards extend the capacity of the existing motherboard. The AGP slot is used to attach a graphic card. The graphic card supports various graphic and display functions of the device. This card improves the graphic functionality of the system. Figure 3,11 shows the PCI slots and AGP slots on a motherboard.

Peripheral Component Interconnect (PCI) Slot

PCI is a bus standard developed by Intel Corporation. PCI slot is 32-bit wide in bus. This slot is used for attaching peripheral devices to the motherboard. Additional components such as Ethernet card, sound card and graphics card can be attached to the motherboard. These slots typically work at 33 MHz. However some newer variants are available that have a 64-bit wide bus and work at 66 MHz or 133 MHz.

PCI Express (PCI-E)

PCI express or PCI-E is the latest Peripheral Component Interconnect Special Interest Group’s (PCISIG) specification for the I/O bus. It is used for attaching peripheral devices to the motherboard. The PCI express extends the capabilities of PCI bus by having 32 differential pair of wires for serial communication. These wires can be combined to form bus architecture of x2, x4, x8, x16 and x32. Prefix ‘x’ is used for lane counts. It has point-to-point, hot-pluggable and hot-swappable system bus that is fully compatible with PCI, at least on the software level. Data Transmission Rate of each lane is 250MBps The initial version of PCI Express supports 0.8V signaling at 2.5GHz. This means x32 connector can transfer data up to 8 GB/s (250 32) in each direction.

CPU Voltage Regulator

Voltage regulator is an electronic Integrated Circuit (IC) that regulates the voltage supplied over a line.

A Voltage Regulator Module (VRM) is installed on the motherboard and regulates the correct voltage that is needed by the CPU. The CPU voltage normally ranges from 12 to 2.5 volts. The regulator maintains this particular voltage range. This module facilitates the mounting of different processors with different operating voltages to be mounted on a motherboard and mostly found on server motherboards whereas voltage regulator ICs are used in desktop motherboards to control the supply voltage given to the processor.

On Board Disk Drive Connectors

The hard drive, floppy drive and the DVD/CD-ROM drive is connected to the motherboard using the on-board disk connectors. The primary connector is used to connect storage devices such as the hard drive and the CD-ROM drive is the Integrated Development Environment (IDE) port on the motherboard. This is also known as the Parallel Advanced Technology Attachment (PATA). The connector is a normal 40 pin connector. A 40 wire connector bus is used to connect the hard drive. Sometimes 80 wire connector bus is also used. The IDE 1 and IDE 2 connectors on the motherboard are used to connect the hard drive and the DVD/CD-ROM drive respectively.

Now days Serial Advanced Technology Attachment (SATA) technology is used to connect SATA drives like hard disk drives and DVD drives. SATA technology supports a transfer rate of upto 1.5 Gbps. New SATA 3.0 version supports transfer rate of 6 Gbps. SATA data cable is a 7 pin connector.


The different connectors on the motherboard enable connection of different devices. The different connectors on the motherboard are; 

  • System panel connector (1)-Accommodates different front panel system functions such as system power LED, hard disk LED, Switch ON, Reset.
  • USB headers (13)-Functions as connectors for USB module that can provide four additional USB ports, if the USB ports are inadequate. 
  • Digital audio connector (3) – Connects to a module that provides digital sound output, instead of analog.
  • MDC connector (4) – Connects to a modem card module.
  • Case Fan connectors (5) – Connects to the system cooling fans.
  • GAME/MIDI connector (6)-Connects to a GAME/MIDI module that can connect to MIDI devices.
  • System Management Bus (SMBus) connector (7) – Used to connect SMBus devices.
  • ATX 12V connector (8)-Connects to the ATX 12V power supply. The power supply plug will fit these connectors in only one orientation.
  • ATX Power Connector (9)-Connects to the ATX power supply.
  • CPU fan connector (10)-Connects to the processor cooling fans.
  • Serial Advanced Technology Attachment (SATA) connectors (11)-Connects the SATA devices.
  •  IDE connectors (12)-Connects to the IDE devices.
  • Floppy disk drive connector (14)-Connects to the floppy drive through the floppy drive ribbon cable.
  • USB Connectors (2)-Connects to USB devices. 
  • Jumpers (3)-Used to change the different functions of motherboard e.g. CMOS clear setting.

Jumpers on the motherboard are small pins that enable you to configure motherboard settings. A jumper consists of a pair of pins and a small shunt. The shunt is placed over the pins to short them. The jumper performs different functions when it is shorted and when it is left open, without the shunt. Jumpers are labeled as J or JP depending upon the motherboard.

Jumpers vary on all motherboards. They perform different functions, have different settings and are positioned differently in every motherboard. Hence, the motherboard manual is a necessity when you deal with jumpers. Clear CMOS jumper allows you to clear the CMOS settings stored in the CMOS. By using this jumper, you can clear the CMOS memory of date, time and system setup parameters. You must not use this jumper unless you want to clear CMOS.

The other jumpers on the motherboard are the USB device wake-up jumpers. You can change the settings on these jumpers to wake the computer from different sleep modes using the connected USB devices.

  1. What is motherboard in a computer?
  2. What are the three types of motherboards?
  3. What are the main functions of motherboard?
  4. What is the cost of motherboard in computer?
  1. The motherboard is a printed circuit board that is the most important part of a system.
  2. Every component of the system connects to the motherboard directly or indirectly.
  3. The different types of motherboard are:
  • Desktop motherboard
  • Server motherboard
  • Laptop motherboard
  1. The leading manufacturers of chipsets include Intel, SiS, VIA and AMD.
  2. The chipset on a motherboard is a group of integrated circuits and microprocessors and also determines the functionality of a motherboard.
  3. The final solution came when the chipset manufacturers started using a new approach: using a dedicated high-speed bus between north and south bridges called DMI and connecting the PCI bus devices to the south bridge.
  4. The North Bridge is replaced by the Memory Controller Hub (MCH) and the South Bridge is succeeded by the I/O Controller Hub (ICH).
  5. The different components on the motherboard can be classified as:
  • CPU Socket
  • Memory Slots
  • Super I/O Chip
  • BIOS Chip
  • CMOS Battery
  • Expansion Slots
  • CPU Voltage Regulators
  1. The Northbridge and Southbridge which constitute a modern chipset are the most important components on the motherboard. The motherboard has a CMOS battery that provides backup power to the CMOS.
  2. You can connect different parts of the system to the motherboard using the connectors and expansion slots. The jumpers on the motherboard enable you to configure the motherboard.
  3. You must follow the instructions in the motherboard manual when performing configuration, installation or troubleshooting of the motherboard.


As a computer engineer, live in Nagpur city, state Maharashtra, country India. country code - +91.
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