Daffodil Computers Ltd.

Frequently Ask Question(FAQ) => Desktop PC => Motherboard => : bbasujon February 19, 2012, 10:52:14 PM

: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:52:14 PM

The main printed circuit board in a computer is known as the Motherboard. It is also known as System Board, Main Board or Printed Wired Board (PWB). Attached to it, we have numerous motherboard components that are crucial in the functioning of the computer.

The motherboard acts as the connection point where major computer components are attached to. It holds many of the crucial components of the system like the processor, memory, expansion slots and connects directly or indirectly to every part of the PC.

The type of motherboard installed in a PC has a great effect on system speed and expansion capabilities.



The motherboard holds all the major logic components of the computer. Here we are going to see with no particular order, some of those major motherboard componets and their function in a computer or to be more precise in your computer.

CPU- Central Processing Unit

It is also known as the microprocessor or the processor. It is the brain of the computer, and it is responsible for fetching, decoding and executing program instructions as well as performing mathematical and logical calculations.

The processor chip is identified by the processor type and the manufacturer; and this information is usually inscribed on the processor chip e.g. Intel 386, Advanced Micro Devices (AMD) 386, Cyrix 486, Pentium MMX, (old processor types) Intel Core 2Duo e.t.c.

If the processor chip is not on the motherboard, you can identify the processor socket as socket 1 to Socket 8, LGA 775 e.t.c. This can help you identify the processor that fits in the socket. For example a 486DX processor fits into Socket 3.


: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:53:01 PM
Main Memory / Random Access Memory (RAM)

Random access memory or RAM most commonly refers to computer chips that temporarily store dynamic data when you are working with your computer to enhance the computer performance. In other words, it is the working place of your computer where active programs and data are loaded so that any time time the processor requres them, it doesn't have to fetch them from the hard disk which will take a longer access time.

Random access memory is volatile memory, meaning it loses its contents once power is turned off. This is different from non-volatile memory such as hard disks and flash memory, which do not require a power source to retain data. When a computer shuts down properly, all data located in random access memory is returned back to permanent storage on the hard drive or flash drive. At the next boot-up, RAM begins to fill with programs automatically loaded at startup, and with files opened by the user a process called booting.

: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:53:39 PM
BIOS- Basic Input Output System

BIOS is a term that stands for basic input/output system, which consists of low-level software that controls the system hardware and acts as an interface between the operating system and the hardware. Most people know the term BIOS by another nameódevice drivers, or just drivers. In other words, the BIOS is drivers, meaning all of them. BIOS is essentially the link between hardware and software in a system.

All motherboards include a small block of Read Only Memory (ROM) which is separate from the main system memory used for loading and running software. On PCs, the BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions.

The system BIOS is a ROM chip on the motherboard used by the computer during the startup routine (boot process) to check out the system and prepare to run the hardware. The BIOS is stored on a ROM chip because ROM retains information even when no power is being supplied to the computer.


: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:54:07 PM
CMOS-Complimentary Metal Oxide Semiconductor

Motherboards also include a small separate block of memory made from CMOS RAM chips which is kept alive by a battery (known as a CMOS battery) even when the PCís power is off. This prevents reconfiguration when the PC is powered on.

CMOS devices require very little power to operate.

The CMOS RAM is used to store basic Information about the PCís configuration e.g.

    Floppy disk and hard disk drive types
    RAM size
    Date and time
    Serial and parallel port information
    Plug and Play information
    Power Saving settings

The Other Important data kept in CMOS memory is the time and date, which is updated by a Real Time Clock (RTC).


: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:54:39 PM
Cache Memory

It is a small block of high-speed memory (RAM) that enhances PC performance by pre-loading information from the (relatively slow) main memory and passing it to the processor on demand.

Most CPUS have an internal cache (in-built in the processor) which is referred to as Level-I cache memory or primary cache memory. This can be supplemented by external cache memory fitted on the motherboard. This is the Level-2 Cache memory or secondary cache. Some CPUs have both L1 and L2 cache built-in and designate the separate cache chip as Level 3 (L3) cache.

: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:55:05 PM
Expansion Buses
An input/output pathway from the CPU to peripheral devices typically made up of a series of slots on the motherboard. Expansion boards (cards) plug into the bus. PCI is the common expansion bus in a PC and other hardware platforms. Buses carry signals, such as data; memory addresses, power and control signals from component to component.

Expansion buses enhance the PCs capabilities by allowing users to add missing features in their computers in form of adapter cards that are slotted in expansion slots.

The different types of buses include PCI, ISA, and EISA expansion bus.

: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:55:33 PM

A chipset is a group of small circuits that coordinate the flow of data to and from key components of a PC. This includes the CPU itself, the main memory, the secondary cache and any devices situated on the buses. The chipset also controls data flow to and from hard disks, and other devices connected to the IDE channels. A computer has got two main chipsets:-

    The NorthBridge (also called the memory controller) is in charge of controlling transfers between the processor and the RAM, which is way it is located physically near the processor. It is sometimes called the GMCH, for Graphic and Memory Controller Hub.

    The SouthBridge (also called the input/output controller or expansion controller) handles communications between peripheral devices. It is also called the ICH (I/O Controller Hub). The tem bridge is generally used to designate a component which connects two buses.

Chipset manufacturers include SIS, VIA, ALI, OPTI e.t.c.

Cpu Clock

The clock synchronizes the operation of all parts of the PC and provides the basic timing signal for the CPU. Using a quartz crystal, the CPU clock breathes life into the microprocessor by feeding it a constant flow of pulses. For example, a 200 MHz CPU receives 200 million pulses per second from the clock. A 2 GHz CPU gets two billion pulses per second. Similarly, in a communications device, a clock may be used to synchronize the data pulses between sender and receiver.

A "real-time clock," also called the "system clock," keeps track of the time of day and makes this data available to the software. A "timesharing clock" interrupts the CPU at regular intervals and allows the operating system to divide its time between active users and/or applications.
: Re: The Major Motherboard Components and their Functions
: bbasujon February 19, 2012, 10:56:44 PM
Switches and Jumpers

DIP (Dual In-line Package) switches are small electronic switches found on the circuit board that can be turned on or off just like a normal switch. They are very small and so are usually flipped with a pointed object such as a screwdriver, bent paper clip or pen top. Care should be taken when cleaning near DIP switches as some solvents may destroy them.


Jumper pins

Jumpers are small pins on the board with plastic or metal devices that go over the pins. This device is called a bridge or a jumper cap. When the bridge is connected to any two pins via a shorting link, it completes the circuit and a certain configuration has been achieved.

Jumper cap

A metal bridge that closes an electrical circuit. Typically, a jumper consists of a plastic plug that fits over a pair of protruding pins. Jumpers are sometimes used to configure expansion boards. By placing a jumper plug over a different set of pins, you can change a board's


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