This article is Chapter 4 in the CompTIA A+ certification course on Alison.com that teaches you an Understanding of Computer Motherboards.

Understanding Motherboards

• Function of motherboards

• A house for everything needed to make a computer operate.
• Contains CPU, RAM memory slots, Cache memory, Chip sets, BIOS/CMOS battery, Expansion slots, Serial/parallel slots, Connectors for mouse & keyboard, sound & video cards, and Fans.
• All necessary in computer to turn inputs to outputs.
• Form factors are used to describe the dimensions and layout of the motherboard components.
• Motherboards are not interchangeable.
• Most common: Advanced Technology Extended (ATX) Motherboard

Location of Primary Components & Motherboard Chipsets

Read the diagram from the top going clockwise:

1. CPU - Central Processing Unit
2. AGP - Advanced Graphics Port
3. PCIe - Peripheral Component Interconnect Express - Interface for connecting Perephrial Devices
4. IDE - Integrated Drive Electronics - Used for storage devices
5. PCI - Peripheral Component Interconnect - Provides a bus for attaching devices to computers
6. USB - Universal Serial Bus - Allows for connections for input and output devices.

North Bridge

• The North Bridge is located close to the CPU.
• Responsible for communication from CPU to Memory.
• Second largest chip after the Processor.
• Usually has a fan or heat sink above it.

South Bridge

• The South Bridge is located farther from the CPU by the PCI slots.
• Responsible for communication between the CPU and other devices such as the IDE, PCI, and other devices.
• Located farther from the CPU, next to PCI slots.

Front and Side Panels

In primary areas, you will connect input and output devices to.

• Audio connections

• Audio port connections such as headphones.

• Drive activity light

• Lets you know whether the system is busy, indicated by a light flashing when the system is reading.

• Power light

• Power on the light and button that lets you know the system is running.

• On/off button

• Lets you turn the system on or off and even perform cold boot if necessary

• USB connections

• Common for universal serial bus connections

Many connections on computers are based on the manufacture of computers and their applicational purpose.

• Power cord

• Supplies power to the motherboard which then supplies power to components on the motherboard.
• Motherboard uses different drives and power connectors like ATX power connectors which come in 3V, 5V, or 12V.

• PCIe connectors

• 6-pin connectors
• Connect things like Graphics and GPU.

• SATA connectors

• which connects external drives through a USB port.
• Different versions you can use.
• Hot-swappable technology (Can remove drivers while the system is running).

Cache Memory

In short, cache memory is used to speed things up.

• Cache memory

• Stores the most frequently accessed data, and makes data access fast for subsequent requests.

• Level I

• All processors have an integrated cache memory known as Level I
• Is built into the processor.
• Not integrated cache, built on the outside of the processor on the motherboard.

• Level II

• Independant memory for the processor core.

• Level III

• Shared cache between each processor core.

RAM Slots

It’s important for the A+ exam to be familiar with the types of sockets, and be able to know how to install the memory.

• RAM slots

• Provide memory for your computer

• Memory slots and sockets

• Used to add additional memory and functionality to the computer.
• Each provides different benefits to the computer or user.

• DIMM

• Dual Inline Memory Module
• Used to install memory
• Manufacturers use a number of these sockets on the motherboard which are usually blue, black, or white.
• Can be installed individually or via the dual channel.
• Dual channel architecture increases performance with the ability to send and receive two 64-bit chunks as opposed to the typical one 64-bit chunk.
• Can be used to speed up and increase capacity.

BIOS Chips

• Basic input/output system BIOS-Chips

• Allow devices to communicate with each other on the motherboard.
• Read-only memory chip, you can’t write data to this chip.
• You can use an Erasable Programable Rom Chip (EPC Rom Chip), available from the manufacturer, and this allows you to update the BIOS if you wanted it to support a larger disk. So it can be rewritten to.
• Primary function of this chip is to control the boot process for the power on self-test.
• This test allows the PC to check out the systems to ensure they are OK.
• After it gives the OK, it locates the bootable partition from the master boot record, which loads the operating system.

Remember:

• RAM

• Random Access Memory
• The computer’s primary working memory
• Temporary in nature

• ROM

• Read Only Memory
• Used to store BIOS
• Used to store power on self-test
• EPROM and the newer EEPROM have software on a chip that can be upgraded using special software from the manufacturer.
• Popular way to update BIOS and hardware as it improves.

Expansion Slots

Do exactly what they sound like.

• Expansion Slots

• Allow the motherboard to expand in functionality by adding additional cards in the expansion slot.
• Use PCI (Peripheral Component Interconnect) like PCI, PCIe, or PCI 16
• PCI is a computer bus for attaching hardware devices in a computer, runs at 33MGH, and is a plug-and-play technology.
• Plug and play / Zif connectors make life easier as a technician.

• Bus architecture

• Terminology used for expansion slots
• You will be installing various cards like network, sound, and video cards. • These include PCI which has a fixed width of 5 bits and can handle 5 devices at a time.
• Other PCI versions can handle higher rates of transfer. • The Personal Computer Memory Card Industry Association (PCMIA), a popular laptop, supports memory cards, network cards, and removable drives. • AGP (Advanced Graphics Port) also supports your video cards • PCI-X & PCI Express support data lanes to transfer information within bus architecture • AMR (Audio Modem Risers) which ads modem and audio cards • CNR (Communication and Network Riser) which is used for local area networks with audio and modem functionality.

Expansions Solts

• Keyboard & Mouse

• These connectors allow users to interact with the computer to produce input and outputs.
• Used to perform operations
• Typically connected through USB and many are wireless today.

• Serial 1 & 2 Ports

• Serial and parallel ports are used to communicate with the motherboard.
• Serial ports send data in series to communication or the COM ports, 1-bit at a time, in a single file.
• Parallel ports send information 8 bits at a time and can send bits side by side in an operation, rather than a single file.
• Serial ports are identified as male ports using pins.
• Most widely used serial communication standard is RS232
• RS485 is used for multi-line or party-line applications.
• Current loop is used for a lower data rate with the absence of voltage current.
• MIL188 is used for military applications
• Parallel ports are identified as 25-pin hole female connections on the back of the motherboard. Commonly used for printer connections.
• Many printers will have a DB25 male connector, with 25 pins on one end, and a 36-pin Centronics connector on the other end.
• Serial 1 & 2 Ports are used to connect devices like: printers, computer displays, GPS receivers, code scanners, POS (Point of Sale ) devices, or even Uninterruptible Power Supplies.

• USB

• USBs are easier because there are no connector pins or screws required and support many modern technologies like: printers, cameras, and recording devices.

Conclusion

You can find free course materials preparing you for the CompTIA A+ exam here: https://alison.com/courses/comptia-a-1000-part-1/

Related Articles:

• 2023/03/16   Chapter 5 - Understanding Processors
• 2023/03/14   Chapter 3 - System Component Overview
• 2023/03/07   What is the CompTIA A+ Certification?
• 2022/07/22   Secure VPS in Ubuntu 20.04: LetsEncrypt, Cloudflare and more
• 2023/03/10   Chapter 2 - Safety for You and Computer Components