Computer Processor

The Computer Motherboard and Its Components Explained

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The computer motherboard is the main printed circuit board (PCB) where most computer components are connected. It provides connectivity between the computer hardware components, for instance, the processor (CPU), memory (RAM), hard drive, and video card.

The motherboard is also known as System Board, Mainboard, Mobo, Main Circuit Board, Planar Board, Logic Board, and Printed Wired Board (PWB) among other names.

It is located at the bottom or on the side of the computer chassis depending on the type of desktop computer you have. The motherboard has many printed wires that carry power and data signals between one component and the other.

It connects directly or indirectly to every part of the Personal Computer. The type of motherboard installed in a PC has a great effect on system speed and future expansion capabilities.

What Is a Computer Motherboard Made Of?

A motherboard is mainly composed of two materials:

  • Layers of fibreglass for insulation.
  • Copper that forms conductive pathways.
Computer Motherboard and Its Components
A Labelled Computer Motherboard

Computer Motherboard Components

The motherboard holds all the major components of the computer. These motherboard components include:

  • The processor (CPU)
  • CPU socket
  • Main Memory (RAM)
  • Memory slot
  • Math Co-Processor
  • BIOS
  • CMOS memory
  • CMOS Battery
  • Expansion slots
  • Cache memory
  • CPU Clock
  • I/O ports
  • Hard disk controllers
  • SATA connector
  • Super I/O chip

Central Processing Unit or the CPU

Also known as the microprocessor, the CPU is the brain of the computer. It fetches, decodes and executes program instructions as well as performs mathematical and logical calculations. The processor is one of the most crucial computer motherboard components.

The CPU chip is identified by the processor type and the manufacturer. This information is usually inscribed on the processor chip, for instance, Intel 386, Advanced Micro Devices (AMD) 386, Cyrix 486, Pentium MMX, Intel Core 2Duo, and Intel Core i7, among others. The processor fits into the processor socket.

Processor, one of the most important computer motherboard components
Intel Core i7 Processor

Processor Socket

A CPU or processor socket is a connection that allows a computer microprocessor to be inserted into the motherboard. There are various types of processor sockets depending on the CPU being inserted. You can identify the processor socket as socket 1 to Socket 8, LGA 775, Socket A, and Socket F, among others.

Main Memory (RAM)

The Main Memory, Primary Memory, System Memory or Random Access Memory (RAM), refers to the physical memory of the computer. The word main is used to distinguish it from external mass storage devices such as disk drives.

Memory is the working place of a computer. It is a hardware device that stores data for easy retrieval. It is volatile meaning it holds data as long as there is power. Once the power goes off or the computer is turned off, all the contents in RAM are lost.

The computer can manipulate only data that is in the main memory. Therefore, every program you execute and every file you access must be copied from a storage device into the main memory. The amount of main memory on a computer is crucial. This is because it determines how many programs can be executed at once and how much data can be readily available to a program.

Memory, another of the most important computer motherboard components
DDR4 SDRAM Module

Types of RAM

There are two broad categories of RAM. These are SRAM and DRAM.

Memory Slot

It is also known as a memory socket or RAM slot. This is the slot or connection point where RAM modules are inserted into the motherboard. There may be two or four RAM slots depending on the motherboard in use.

Math Coprocessor

The Math coprocessor is a type of microprocessor that is optimized to execute complex mathematical calculations for instance irrational numbers and arrays. It was an optional add-on for earlier Intel processors such as 8086, 80386 and 80486.

This allowed computers to perform mathematical calculations faster. It is also referred to as a numeric coprocessor or a floating-point coprocessor. Modern computer processors come with an integrated math coprocessor.

The 486DX processor was the first processor to include an in-built math co-processor (inside the CPU). The earlier processors 8088, 8086, 80286, 80386SX & DX, and 486SX had their math co-processors on the motherboard.

A math Coprocessor found on older types of motherboards.
Intel C8087 Math Coprocessor – Source

Basic Input Output System – BIOS

BIOS is a term that stands for basic input/output system. It consists of low-level software that controls the system hardware and acts as an interface between the operating system and the hardware. The microprocessor uses BIOS to get the computer started after it is turned on.

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 several miscellaneous functions.

BIOS is Stored in a ROM Chip

The BIOS is stored on a ROM chip because ROM retains information even when no power is being supplied to the computer. The downside of storing data in an older computer’s ROM is that the chip has to be removed to update information. Many modern PCs have flash BIOS, which means that the BIOS has been recorded on a flash memory chip, which can be updated if necessary.

The BIOS is typically placed in a ROM chip that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures.

It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. This is known as shadowing.

AMIBIOS – Source: By © Raimond Spekking / CC BY-SA 4.0 (via Wikimedia Commons), CC BY-SA 4.0

The PC BIOS is fairly standardized, so all PCs are similar at this level (although there are different BIOS versions).

Some Bios Hardware Configuration Options That Can Be Changed

  • Change the Boot Order
  • Load BIOS Setup Defaults
  • Remove a BIOS Password
  • Create a BIOS Password
  • You can change the Date and Time
  • Change Floppy Drive Settings – nowadays obsolete
  • To change Hard Drive Settings
  • Changing CD/DVD/BD Drive Settings
  • View Amount of Memory Installed
  • Change the Boot Up NumLock Status
  • Enable or Disable the Computer Logo
  • Enable or Disable the Quick Power-On Self-Test (POST)

Unified Extensible Firmware Interface (UEFI)

This is a specification for a software program that connects a computer’s firmware to its operating system. It is expected to replace BIOS.

UEFI is installed at the time of manufacturing and just like BIOS; it is the first program that runs when a computer is powered on. UEFI checks for the hardware components installed on the computer.

It wakes up the available devices and hands them over to the operating system. It is programmable and hence developers can add applications and drivers. This makes UEFI function as a lightweight operating system. It is managed by a group of chipset, system, hardware, firmware, and operating system vendors called the UEFI Forum.

Advantages of UEFI

  • It comes with a user–friendly, graphical user interface.
  • It recognizes large storage drives over two terabytes.
  • UEFI can support remote diagnostics and repair of computers, even with no operating system installed.
  • You can use a mouse in the interface
  • It comes with a secure boot feature
What’s the difference between BIOS, CMOS, and UEFI ?

Complementary Metal Oxide Semiconductor – CMOS

Motherboards also include a small separate block of memory made from CMOS RAM chips. Other names of the CMOS are RTC (real-time clock), NVRAM (non-volatile RAM) or CMOS RAM.

It stores information about the BIOS settings. The CMOS RAM is kept alive by the CMOS battery even when the PC’s power is off. This prevents reconfiguration when the PC is powered on. CMOS devices require very little power to operate.

The CMOS RAM Stores

The CMOS Ram stores basic information about the PC’s configuration. This is for instance;

  • Floppy disk and hard disk drive types
  • CPU
  • 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).

Complementary Metal-Oxide-Semiconductor
Complementary Metal-Oxide-Semiconductor

Cache Memory

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

Most CPUs have an internal cache (in-built into 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. Even though Level-2 cache is optional, it results in a major improvement in system performance.

Expansion Buses

An expansion bus is an assortment of wires that allows for computer expansion with the use of an expansion board. Expansion buses give rise to expansion slots.

Expansion boards are inserted into an expansion slot on the motherboard or backplane that provides additional features to a computer system. Buses carry signals, such as data; memory addresses, power, and control signals from component to component.

Expansion buses enhance the PC’s capabilities by allowing users to add missing features to their computers in the form of adapter cards that are slotted in expansion slots. The different types of buses include PCI, ISA, EISA, and Input/Output (I/O) buses among others.

Example of a PCI digital I/O expansion card – Source:

Expansion Slots

Alternatively referred to as a bus slot or expansion port, an expansion slot is a connection or port located on the motherboard. It is where an expansion card is inserted.

A PCI slot
PCI slot where you insert a PCI card– Source

Chipset

A chipset is a group of small circuits that coordinates the flow of data and instructions between the central processing unit (CPU) or microprocessor and external devices. 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.

Chipset manufacturers include Intel, UMC, SIS, VIA, ALI, OPTI, etc. The chipset originally was made up of a large number of electronic chips, hence the name. A chipset generally has two components:

  • The NorthBridge (also called the memory controller) is in charge of controlling transfers between the processor and the RAM. That is why 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 term bridge is generally used to designate a component which connects two buses.

CPU Clock

The CPU clock is an internal timing device that breathes life into the microprocessor by feeding it a constant flow of pulses. For example, a 400 MHz CPU receives 400 million pulses per second from the clock. A 2 GHz CPU gets two billion pulses per second.

The clock synchronizes the operation of all parts of the computer and provides the basic timing signal for the CPU. Similarly, in a communications device, a clock may be used to synchronize the data pulses between sender and receiver.

Switches

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. They are usually used to make or break a connection within a circuit.

Jumper Pins

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

Circuit Board Jumper Caps/ Shunts 

A jumper cap is a metal connector that closes an electrical circuit. Typically, a jumper cap consists of a metal connector encased with a plastic covering. They are designed to fit over a pair of protruding pins (jumper pin). 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 parameters.

Jumpers caps are used to configure a boards parameters
Circuit Board Jumper Caps / Shunts 

3-Pin Case Fan Connectors

These pins are for connecting the case fan also known as the system fan. The system fan is used to bring in cool air and blow out hot air from the system unit. This helps cool the computer motherboard components.

Heat Sink

A heat sink is a device made of an aluminium finned radiator used to absorb excessive or unwanted heat from some computer motherboard components. There are two types of heat sinks, active and passive heat sinks.

Passive heat sinks have no mechanical components, just aluminium-finned radiator material. On the other hand, active heat sinks utilize the computer’s power and may come with a fan mounted on top.

A passive heat sink as seen on a motherboard
A passive heat sink

24-Pin ATX Power Supply Connector

This is where you connect the ATX power supply to the motherboard. The corresponding connector has a small clip on the top that snaps to hold the connector in place. The connector is keyed to ensure it connects in one direction.

Computer power connector as found in Computer Motherboard and Its Components
ATX power connector

SATA Connectors

This is the connection point for mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier IDE connectors that used Parallel ATA (PATA) standard to become the predominant interface for storage devices.

Close-up of SATA data and power connectors as found in Computer Motherboard and Its Components
SATA Connector

Super IO Chip

This type of controller is an integrated circuit found on the computer motherboard. It handles the slower and less prominent input/output devices such as floppy disk controller, game port, parallel port, real-time clock, and serial port UART among others.

Components Of The Motherboard

Well, those are just some of the computer motherboard components. You will find others not discussed here because we have different types of motherboard designs.

The Central Processing Unit (CPU) And Its Components Explained

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The Central Processing Unit (CPU) is one of the most important components of a computer. It is known by several names such as central processor, main processor, microprocessor, or just processor.

The computer processor is a small chip (logic circuitry) that resides in computers and other electronic devices.

Its basic function is to receive and process basic instructions that drive a computer. It is among the most important components inside the computer.

It processes information and interfaces with other system elements to retrieve data to be processed. The speed of the processor is a major factor in determining the performance of the PC.

A Computer Processor
A Computer Processor

Generally, the Central Processing Unit Performs the Following Functions:

  • Decodes and executes instructions obtained from software programs.
  • Performs arithmetic calculations.
  • Controls and supports the timing of each operation.

What is Meant by a Computer Processor?

A processor is an integrated electronic circuit that performs the calculations that run a computer. The processor is a flat plate of silicon made up of millions of transistors. The transistors are etched onto the plate in a huge computer logic framework.

Ceramic material is used to cover the microcircuit. It protects and also conducts heat away to the heat sink. This protective ceramic cover has print information on the processor type and other useful information.

How the Computer Processor Operates

The basic operation of most computer processors, regardless of their physical form, is to execute a sequence of stored instructions called a program. The instructions to be executed are kept in computer memory.

Nearly all CPUs follow the fetch, decode and execute steps in their operation, which are collectively known as the instruction cycle.

After the execution of an instruction, the entire process repeats. The next instruction cycle normally fetches the next-in-sequence instruction because of the incremented value in the program counter.

If a jump instruction was executed, the program counter will be modified to contain the address of the instruction that was jumped to and program execution continues normally. In more complex CPUs, multiple instructions can be fetched, decoded, and executed simultaneously.

Fetch Cycle

The fetch execute cycle of computer processor
The Fetch Execute Cycle – Attribution

The first step a processor does is to fetch. It involves retrieving an instruction (which is represented by a number or sequence of numbers) from program memory.

The program counter (PC) determines the instruction’s location (address) in program memory. 

This counter stores a number that identifies the address of the next instruction to be fetched.

After an instruction is fetched, the PC is incremented by the length of the instruction so that it will contain the address of the next instruction in the sequence. 

Most often the instruction is retrieved from relatively slow memory. This action causes the CPU to stall while waiting for the instruction to be returned.

This issue is largely addressed in modern processors by the use of cache memory and pipeline architectures.

Decode Cycle

The instruction fetched by the central processing unit from memory determines what the processor will do.

In the decode step, performed by the circuitry known as the instruction decoder, the instruction is converted into signals that control other parts of the CPU.

The CPU’s instruction set architecture (ISA) defines how the instruction is to be interpreted. Often, one group of bits (that is, a “field”) within the instruction, called the opcode, indicates which operation is to be performed.

The remaining fields usually provide supplemental information required for the operation, such as the operands. Those operands may be specified as a constant value (called an immediate value), or as the location of a value that may be a processor register or a memory address, as determined by some addressing mode.

Execute Cycle

After the fetch and decode steps, the execute step is performed. Depending on the CPU architecture, this may consist of a single action or a sequence of actions.

During each action, various parts of the central processing unit are electrically connected. This enables them to perform all or part of the desired operation and then the action is completed. This is usually in response to a clock pulse.

Results are written to an internal CPU register for quick access by subsequent instructions. In other cases, results may be written to slower, but less expensive and higher capacity main memory.

Components of the Central Processing Unit

In the CPU, there are two primary components namely the Arithmetic Logic Unit and Control Unit.

CU (Control Unit)

The control unit controls all the operations taking part in the computer. However, it does not carry out any actual data processing operations.

  • It controls the transfer of data and instructions among other units of the computer.
  • The control unit manages and coordinates all the units of the computer.
  • It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
  • It communicates with Input / Output devices for the transfer of data or results from storage.

ALU (Arithmetic Logic Unit)

The Arithmetic Logic Unit consists of two sections namely the Arithmetic unit and Logic unit.

Arithmetic Unit

The arithmetic section performs arithmetic operations like addition, subtraction, multiplication, and division. All complex operations are done by making repetitive use of the above operations.

Logic Unit

The function of the logic unit is to perform logic operations such as comparing, selecting, matching, and merging data.

Components of the Central Processing Unit
Components of the Central Processing Unit

What Factors Affect Central Processing Unit Performance?

Modern-day processors are extremely fast though their performance can be affected by several factors.

Clock Speed

Clock speed is also referred to as clock rate, PC frequency and CPU frequency. The clock speed (or clock rate) is stated in megahertz (MHz) or gigahertz (GHz).

It refers to the speed at which the processor can execute instructions. The faster the clock, the more instructions the processor can complete per second.

Most CPUs are synchronous circuits, which means they employ a clock signal to pace or control their sequential operations.

An external oscillator circuit generates the clock signal. This circuit generates a consistent number of pulses each second in the form of a periodic square wave.

This frequency of the clock pulses is the one that determines the rate at which a CPU executes instructions.

Instruction Set of the Computer Processor

This is the processor’s built-in code that tells it how to execute its tasks. It is an architectural design coded into the chip during the manufacturing process.

The processor’s architecture and instruction set determines how many cycles are needed to execute a given instruction.

Bandwidth

Bandwidth is measured in bits. It determines how much information the processor can process in one instruction. A good analogy is to compare data flow to the flow of traffic on a highway.

The clock speed is the speed limit, and bandwidth is the number of lanes on the highway. Computer processors are either 32-bit or 64-bit CPUs.

Cache Memory

Cache memory is a relatively small amount of high-performance SRAM (Static Random Access Memory) built directly into the processor. It enables the processor to access repeatedly used data directly from its onboard memory.

This is as opposed to repeatedly requesting it from the system RAM. In the early days of computing, processors were getting faster, but the memory was not. To address this problem, engineers put tiny amounts of fast memory on the processor itself.

The level 1 cache is the smallest and fastest RAM on the computer. It stores the information that a particular core of the processor is most likely to require to complete its present task.

The level 2 cache is larger, but not quite as fast. It holds the information the processor core is most likely to need to complete its next task. Level 3 is much larger but slower.

Number of Cores

A core is a processing unit within a CPU. Each core is capable of fetching, decoding and executing its instructions. The more cores a CPU has, the greater the number of instructions it can process.

Many modern CPUs are dual (two) or quad (four) core processors. This yields superior processing power compared to CPUs with a single core.

A core 2 Duo processor
An Intel Core 2 Duo E7500 “Wolfdale-3M”

Front Side Bus (FSB) Speed

The FSB is the interface between the processor and the system memory. The FSB speed limits the rate at which data can get to the CPU.

This in turn limits the rate at which the CPU can process that data. The CPU’s FSB speed determines the maximum speed at which it can transfer data to the rest of the system.

How to Install a New Central Processing Unit

Installing a new CPU is becoming less common but it is not a thing out of the normal. In many cases, installing additional memory is a more effective upgrade than installing a new CPU.

However, there are times you will find yourself in need of installing a new processor. If you are assembling your PC, you will install it yourself.

Before you make any purchase, determine whether the CPU can be upgraded and, if so, to what. The answer to this question lies in the motherboard.

The motherboard must have the appropriate socket, data bus; address bus, and crystal to support the new CPU.

Consult the documentation that comes with the motherboard. Ensure that a table defining the processors that can be installed is present. You can also consult the motherboard manufacturer either through the company’s Web site or via a phone call.

A fan-cooled heat sink on the processor
A fan-cooled heat sink on the processor of a personal computer

General Procedure for Installing a Central Processing Unit

1. Turn off the computer and unplug the power cord to the system unit.

2. Follow the appropriate ESD safety procedures. If you have no antistatic kits, just ground yourself by touching the unpainted metal of your computer or touching a metal water tap.

3. Remove the cover of the computer.

4. Locate the CPU to be removed. It will always be under the metal heat sink with a cooling fan attached.

5. Remove any cables, components or drives that might hinder a smooth operation. Note how everything is connected.

6. Unplug the cooler from the motherboard.

7. Detach the lever on the side of the CPU socket cover to allow you to remove the CPU.

You are Almost Done on Installing a Central Processing Unit

8. Install the new computer processor, and align the chip properly. Pin 1 on the CPU must fit pin 1 in the socket. There are indicators on the CPU and socket to help you get the alignment correct. Look for a matching indicator on the corner of your CPU and the socket.

It will likely appear as a small triangle. If you don’t see any indicator, you should consult the manuals for your motherboard and CPU. If you have lined up your CPU with the socket, it should drop right into place.

9. Once the CPU is properly seated in the socket, push down the retention arm with ease (and if it’s an Intel CPU, lower the bracket first).

10. Apply the thermal paste on top of the processor. This helps conduct heat from the processor to the CPU cooler by removing any imperfections on the contact surfaces. Place the heat sink and fan.

11. Reattach the components, cables, and drives you disconnected.

12. Reconnect any peripherals (keyboard, mouse, and monitor).

13. Close your fingers and power up your computer.

How to install a CPU

Some Central Processing Unit Manufacturers / Designers

Apart from Intel’s range of processors, there are other manufacturers such as:

  • Advanced Micro Devices (AMD)
  • Cyrix
  • Integrated Device Technology (IDT)
  • Qualcomm
  • NVIDIA
  • IBM
  • Samsung
  • Motorola
  • Hewlett-Packard (HP)
  • Dell
  • Acer
  • VIA
  • Marvell
  • Global Foundries
  • Media Tek

Each of these offers competitively priced processor chips with comparable performance to Intel processors.

Conclusion

The form, design, and implementation of CPUs will indeed keep changing over time, but their basic operation remains almost unchanged. Hope you have enjoyed this article.

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