This section will help you understand what is physically inside a computer and what each part does. After reading the information in this module, you should be able to answer one core question:

What are the major parts of a computer and what does each one do?

The Motherboard: The Computer's Foundation

Core Concept

The motherboard is the main circuit board that connects all the components of a computer together. It allows the CPU, RAM, storage, and other components to communicate with each other.

Every component in the computer either:

• plugs into the motherboard OR
• connects to the motherboard

Without the motherboard, the computer cannot function. 

Find a picture of a motherboard by looking up the word "motherboard" in a Google search. What do you see in the picture? Are there components connected to the motherboard? 

Important Acronyms

CPU — Central Processing Unit - The CPU is the main processor of the computer that executes instructions and performs calculations. It controls how software runs and processes the tasks requested by the operating system and applications.

RAM — Random Access Memory - RAM is temporary memory that stores data the CPU is actively using. When the computer turns off, everything stored in RAM is erased.

PCIe — Peripheral Component Interconnect Express - PCIe is a high-speed expansion slot on the motherboard used to connect additional hardware components. Devices such as graphics cards, network cards, and storage expansion cards use PCIe connections.

BIOS — Basic Input Output System - The BIOS is firmware stored on the motherboard’s BIOS chip that starts the computer and checks that hardware components are functioning before the operating system loads.

UEFI — Unified Extensible Firmware Interface - UEFI is the modern replacement for BIOS that provides faster startup, improved security features, and support for newer hardware technologies.

The CPU: The Brain of the Computer

Core Concept

The CPU (Central Processing Unit) is the component that performs calculations and executes instructions. The brain of the computer.

Every action the computer performs must be processed by the CPU.

Examples:

• opening a program
• running software
• loading a webpage
• processing data
  

Important Acronyms

CPU — Central Processing Unit - The CPU installs directly into a socket on the motherboard and performs the computer’s main processing tasks. The brain of the computer.

GHz — Gigahertz - Gigahertz is a measurement of processor speed that indicates how many billions of cycles a CPU can perform each second. A higher GHz generally means the processor can handle more instructions per second.

ALU — Arithmetic Logic Unit - The ALU is a part of the CPU that performs mathematical calculations and logical comparisons. It handles operations such as addition, subtraction, and decision-making processes used in computing.

CU — Control Unit - The Control Unit is a component inside the CPU that directs how instructions move through the processor. It coordinates communication between the CPU, memory, and other hardware.

ARM — Advanced RISC Machines - ARM is a processor architecture designed for efficiency and low power usage. It is commonly used in smartphones, tablets, and many modern low-power computers.

RAM: The Computer's Short-Term Memory

Core Concept

RAM (Random Access Memory) temporarily stores information that the CPU is actively using. 

The more RAM a computer has, the more tasks it can handle at the same time.

RAM is temporary memory, meaning data disappears when the computer shuts off or electricity is removed. A word you’ll see commonly used is volatile memory.

Important Acronyms

RAM — Random Access Memory is temporary storage of information that the CPU needs to process.

DIMM — Dual Inline Memory Module is a standard circuit board containing RAM chips that plugs directly into a motherboard’s memory slots, commonly referred to as a "stick of RAM".

DDR — Double Data Rate RAM processes information on the down and up cycle of a pulse of electricity.

DDR3 / DDR4 / DDR5 — RAM generations (as noted by the number). Each generation means a new release with more efficiency, speed, and other benefits.

Storage: Where Data Lives Permanently

Core Concept

Storage devices hold data permanently, even when the computer is turned off.

Storage contains:

• operating systems
• programs
• files
• photos
• documents
  
  

Types of Storage

HDD

HDD — Hard Disk Drive
Uses spinning magnetic disks to store data.

SSD

SSD — Solid State Drive
Uses flash memory chips and has no moving parts.

Important Acronyms

HDD — Hard Disk Drive - An HDD is a storage device that uses spinning magnetic disks to store and retrieve data. It has moving parts and is generally slower than solid-state storage.

SSD — Solid State Drive - An SSD stores data using flash memory chips instead of spinning disks. Because it has no moving parts, it is faster, quieter, and more durable than an HDD.

NVMe — Non-Volatile Memory Express - NVMe is a high-speed storage protocol designed for modern solid-state drives. It allows SSDs to communicate with the CPU much faster than older storage interfaces.

SATA — Serial Advanced Technology Attachment - SATA is a common interface used to connect storage devices like HDDs and SSDs to the motherboard. It provides a standardized way for drives to transfer data with the computer.

Power Supply: The Computer's Electricity Source

Core Concept

The Power Supply Unit (PSU) converts electricity from a wall outlet into usable power for the computer.

It distributes power to:

• motherboard
• CPU
• storage
• GPU

• fans

Without the power supply, the computer cannot turn on.

Important Acronyms

PSU — Power Supply Unit - The PSU converts electricity from a wall outlet into usable power for computer components. It distributes power to the motherboard, CPU, storage drives, and other hardware.

AC — Alternating Current - AC is the type of electrical current delivered by wall outlets in homes and buildings. The power supply converts AC into DC so the computer components can use it.

DC — Direct Current - DC is the type of electrical current required by computer components to operate. The power supply converts incoming AC power into stable DC power.

GPU: The Graphics Processor

Core Concept

The GPU (Graphics Processing Unit) processes images, video, and graphics.

It is responsible for:

• displaying images on the screen
• video rendering
• gaming graphics
• graphic design
• video editing

Some computers have integrated GPUs built into the CPU.

Others have dedicated GPUs installed as expansion cards.

Important Acronyms

GPU — Graphics Processing Unit - The GPU is a specialized processor designed to handle graphics, images, and video. It performs calculations needed to render visuals that appear on a computer monitor.

VRAM — Video Random Access Memory - VRAM is memory located on a graphics card that stores image data and textures used by the GPU. It helps the GPU quickly access visual information while rendering graphics.

PCIe — Peripheral Component Interconnect Express - Most graphics cards connect to the motherboard through a PCIe slot, which allows high-speed communication between the GPU and the rest of the system.

PCIe: How Expansion Cards Connect

Core Concept

PCIe (Peripheral Component Interconnect Express) is a high-speed connection slot on the motherboard.

It allows additional hardware to be installed into the computer.

Examples:

• GPU
• network cards
• sound cards
• storage expansion cards
  

Important Acronyms

NIC — Network Interface Card - A NIC is a hardware component that allows a computer to connect to a network. It can provide either wired Ethernet connectivity or wireless networking capabilities.