✅ Programs, the CPU, and Memory (Beginner Study

Notes)
What is a Program?

• A program is a set of instructions that tells a computer what to do (e.g., Chrome,

Word, or a game).
• Programs are stored on long-term storage like hard drives, similar to storing recipes
in a cookbook.

CPU – The Chef of the Computer

• The CPU (Central Processing Unit) is like a chef that reads and executes
instructions from the program.
• The faster the CPU, the faster it processes these instructions.

RAM – Short-Term Memory

• RAM (Random Access Memory) stores temporary data and instructions that the CPU
needs right now.
• Think of RAM as the chef’s kitchen counter – it’s faster to use than going back to
the cookbook (hard drive) each time.

How the CPU Executes Instructions

1. The program is copied from the hard drive to RAM.

2. The CPU pulls one instruction at a time from RAM.
3. Each instruction is in binary (1s and 0s) – machine language the CPU understands.

External Data Bus (EDB)

• The EDB is a set of wires that carries binary data between components (like veins in a
body).
 • A "1" means voltage (ON), "0" means no voltage (OFF).

Think: EDB = High-speed road for 1s and 0s between CPU and memory.

Registers – CPU's Work Tables

• Registers are tiny storage spots inside the CPU where data is held while processing.
• Example: Add 2 + 3
o 2 stored in Register A, 3 in Register B, result 5 in Register C.

MCC (Memory Controller Chip)

• Acts like a messenger between the CPU and RAM.

• CPU asks for data → MCC finds it in RAM → Sends it via EDB to CPU.

Address Bus vs Data Bus

• Address Bus = tells RAM where to find the data.

• Data Bus = carries the actual data back to the CPU.

Cache – Ultra-Fast Memory

• Cache is small memory inside the CPU for frequently used data.
• It’s faster than RAM, like keeping snacks in your pocket instead of the fridge.

Types of CPU Cache

Level Speed Size Used for

L1 Fastest Smallest Instructions currently being executed
L2 Faster Medium Recently used data
L3 Fast Largest Shared by all CPU cores

Clock and Clock Cycle

• CPU has a clock wire that ticks to keep operations in sync.

• Each tick = one CPU operation (called a clock cycle).
 • 3.4 GHz = 3.4 billion clock cycles per second.

Overclocking

• Overclocking = running the CPU faster than its rated speed.

• Increases performance but can cause overheating or damage if not done carefully.

✅ Supplemental Reading: CPU Cache and Overclocking

(Expanded Beginner Notes)

What is Cache?

• Cache = small, fast memory storing recently accessed data.

• Reduces wait time by avoiding slow access to RAM or hard drive.

CPU Cache (Again, More Detail)

• Cache is built inside the CPU core.

• Helps CPU quickly access important data without checking RAM every time.

Levels of CPU Cache (L1, L2, L3)

Visual:

CPU Core
┌──────────────┐
│ L1 Cache │ ← Fastest (per core)
│ L2 Cache │ ← Fast (per core)
└──────┬───────┘
↓
Shared L3 Cache ← Slower but large (shared across cores)

Overclocking Explained

• Overclocking: Forcing CPU to run faster (e.g., 3.2 GHz → 3.5 GHz).
• Useful in gaming, video editing, or heavy tasks.
• More cycles/second = more instructions processed.
 Key Overclocking Terms

Term Meaning
Base Clock Standard operating speed (e.g., 3.2 GHz)
Core Multiplier Multiplier applied to base clock to get actual speed
Core Voltage Power needed to support increased clock speed

Risks of Overclocking

• Overheating if cooling isn’t upgraded.

• System crashes or instability.
• Shorter lifespan of CPU and may void warranty.

Absolutely! Here's a step-by-step, beginner-friendly breakdown of:

✅ How to Overclock a CPU Safely (Expanded Steps)

Overclocking means running the CPU faster than its rated speed to boost performance — but
it must be done carefully to avoid damage.

Step 1: Check If Overclocking is Supported

Why: Not all CPUs or motherboards allow overclocking.

• ✅ For Intel CPUs: Only models with a K (e.g., i5-11600K) or X in the name are
unlocked.
• ✅ For AMD CPUs: Most Ryzen CPUs support overclocking.

Check:

• CPU specs on Intel/AMD websites.

• Motherboard manual to ensure it supports CPU multiplier/voltage changes.

Step 2: Clean the Inside of the Computer

 Why: Dust buildup increases heat, which can cause overheating during overclocking.

• Turn off and unplug the PC.

• Wear an anti-static wrist strap to prevent static damage.
• Open the case and blow out dust using compressed air, especially:
o CPU area
o Cooling fans
o Air vents

Step 3: Upgrade CPU Cooling (CRITICAL)

Why: Overclocking increases heat output significantly.

Stock coolers (default fans) are not enough.

✅ Use one of:

• High-performance air cooler

• Liquid cooling system (more expensive but better cooling)

Good cooling = stable performance and prevents CPU damage.

Step 4: Benchmark the System

Why: You need to know how your system performs at normal (non-overclocked) speeds
first.

Use benchmarking software like:

• Cinebench
• CPU-Z
• HWMonitor
• AIDA64

Record:

• CPU speed
• Temperature (°C)
• System stability under load

This is your baseline for comparison.

 Step 5: Open BIOS or Use Software

You can overclock via:

• BIOS (usually more stable and powerful)

• Software utilities like:
o Intel XTU (Extreme Tuning Utility)
o AMD Ryzen Master

To enter BIOS:

• Restart computer → Press Delete, F2, or F10 during boot.

Step 6: Lower All Core Multipliers Initially

The Core Frequency = Base Clock × Multiplier

Example:
Base Clock = 100 MHz
Multiplier = 32
→ Frequency = 100 × 32 = 3200 MHz = 3.2 GHz

Start by:

• Setting all CPU core multipliers to the same low value.

• Reboot the system to test stability.

Step 7: Increase Multiplier Gradually

Slowly raise the multiplier by 1 or 2 at a time.

Example:

• Try 33 (3.3 GHz), then 34 (3.4 GHz), and so on.

After each increase:

• Save settings.
• Reboot.
• Run stress tests (like Prime95 or AIDA64).
• Monitor temperature (don’t let it go over 85–90°C under load).
 Step 8: Increase Voltage Only If Necessary

If the system becomes unstable:

• Increase core voltage (vCore) in small steps:

o Try +0.01V or +0.02V increments.
• Never go above 1.4V without advanced cooling.

Higher voltage = more heat = more risk.

Step 9: Watch for Crashes or Freezes

If the computer:

• Crashes
• Freezes
• Gets BSOD (blue screen of death)

→ It’s unstable.

Fix by:

• Going back to the last stable multiplier/voltage.

• Or slightly increasing voltage if temps are safe.

Step 10: Save Settings & Final Test

✅ Once stable:

• Save BIOS settings.

• Reboot and do a final long stress test (1–2 hours).

Monitor:

• Temperature (should stay under 85°C)

• No crashes or thermal throttling
✅ Summary Flowchart
Check CPU & motherboard support
↓
Clean inside of PC
↓
Install high-performance cooling
↓
Benchmark current performance
↓
Enter BIOS or use software
↓
Set low starting multiplier
↓
Gradually increase multiplier
↓
Stress test after each increase
↓
If unstable → raise voltage slightly
↓
If still unstable → reduce speed
↓
Stable? → Save settings → Done!

1. What is a CPU?

• The CPU (Central Processing Unit) is the “brain” of the computer.

• It processes instructions and calculations, like a super-fast calculator that handles
binary data.
• Every program is broken into simple instructions that the CPU can run (called the
instruction set).
• Different CPUs may use different instruction sets but perform similar tasks (like
adding, copying data).

2. CPU Manufacturers and Models

• Popular CPU makers: Intel, AMD, Qualcomm, Apple.

• Examples of CPU lines: Intel Core i7, AMD Athlon, Snapdragon 810, Apple A8.
• Each CPU has strengths and weaknesses depending on design and purpose.

3. CPU and Motherboard Compatibility

• CPUs must fit the socket on the motherboard to work together.

• Two main socket types:
o LGA (Land Grid Array): Pins are on the motherboard.
 o PGA (Pin Grid Array): Pins are on the CPU itself.
• Always check CPU and motherboard compatibility (socket type and model) before
buying.

Diagram: CPU sockets

+-------------------------+ +---------------------------+
| Motherboard (LGA socket) | <---> | CPU with flat contact pads |
| [Pins protrude here] | | No pins on CPU bottom |
+-------------------------+ +---------------------------+

+-------------------------+ +---------------------------+
| Motherboard (PGA socket) | <---> | CPU with pins on bottom |
| [Flat contacts here] | | [Pins stick out on CPU] |
+-------------------------+ +---------------------------+

4. CPU Cooling

• CPUs get hot during operation because they work hard.

• Heat sinks and fans remove heat to keep the CPU cool and prevent damage.
• Good cooling is essential, especially if you overclock the CPU (run it faster than
designed).

5. 32-bit vs 64-bit CPU Architecture

• Architecture defines how much data the CPU can process at once.
• 32-bit CPU: Processes 32 bits (binary digits) at a time.
• 64-bit CPU: Processes 64 bits at a time — can handle more data and memory
efficiently.
• 64-bit CPUs are faster and can support more RAM (over 4 GB), important for modern
computing.

6. Choosing 32-bit vs 64-bit Software (like Microsoft Office)

• 64-bit software can access more memory and handle larger files (better for big data,
videos, complex spreadsheets).
• 32-bit software is compatible with older add-ins, tools, and systems with less RAM.
• If your PC has 64-bit Windows and sufficient RAM (4 GB+), 64-bit Office is
generally better.
• If you use legacy add-ins or old hardware, 32-bit might be needed.
Practical IT Support Tip

• When installing or troubleshooting software, always confirm whether your system

and applications require 32-bit or 64-bit versions to avoid compatibility issues.

Flow Diagram 1: How to Check CPU Compatibility with Motherboard

Start
│
▼
Identify CPU model and socket type (e.g., LGA 1200, AM4) ← Usually on CPU
box or manufacturer website
│
▼
Identify motherboard model and socket type (e.g., LGA 1200, AM4) ← Check
motherboard box/manual or website
│
▼
Do CPU socket and motherboard socket types match?
├── No ──► CPU and motherboard are NOT compatible → Need to select a
matching CPU or motherboard
│
└── Yes ──► Proceed to check BIOS support and power requirements
│
▼
Is motherboard BIOS updated to support CPU model?
├── No ──► Update BIOS firmware (check manufacturer instructions)
│
└── Yes ──► CPU is compatible with motherboard → Ready to install

Flow Diagram 2: How to Choose Between 32-bit and 64-bit Software

Start
│
▼
What is your operating system type?
├── 32-bit OS ──► Must use 32-bit software (64-bit won’t run)
│
└── 64-bit OS ──► Continue
│
▼
How much RAM do you have?
│
├── Less than 4 GB ──► 32-bit software recommended (less memory usage)
│
└── 4 GB or more ──► Continue
│
▼
Do you need to use legacy add-ins or plugins only available in 32-bit?
│
├── Yes ──► Choose 32-bit software for compatibility
│
└── No ──► Choose 64-bit software for better performance and memory use
 What is RAM?
• RAM = Short-term memory of a computer.
• It temporarily stores data and instructions that the CPU actively uses.
• Data in RAM is volatile: it's erased when the computer is shut down or loses power.

Analogy: RAM is like your desk. You place things you're working on now (open files,
notebooks). Once you're done (or the power goes off), the desk is cleared.

Why is RAM needed?

• Every time you open a program, the system copies it from the storage (HDD/SSD)
to RAM so the CPU can quickly access and process it.
• RAM provides fast read/write access, much faster than storage.

What happens without enough RAM?

• System becomes slow, programs lag or freeze, and you may see error messages like
“out of memory.”
• The OS may use virtual memory (part of storage) as backup, which is much slower.

Real-life examples:
• Opening multiple browser tabs, games, or apps uses RAM.
• Unsaved work in Word or PowerPoint is stored in RAM until saved.
• Ever lost work during a power cut? It was in RAM and never saved to disk.

Types of RAM:
Type Description

Common RAM in computers. Stores bits in capacitors (charge = 1, no

DRAM (Dynamic RAM)
charge = 0). Needs refreshing thousands of times per second.
 Type Description

Faster but expensive. Used in CPU cache, not main RAM. Doesn't need
SRAM (Static RAM)
constant refreshing.

SDRAM (Synchronous
Synchronized with system clock = faster.
DRAM)

DDR SDRAM (Double Data

Sends data twice per clock cycle. Most common today.
Rate SDRAM)

Each newer generation is faster, uses less power, and has higher
DDR1/2/3/4/5
capacity. DDR4 is standard; DDR5 is emerging.

RAM Size & Performance:

• More RAM = better multitasking and faster app performance.
• Examples:
o 4 GB: Basic use (email, browsing)
o 8 GB: Moderate use (Office, light gaming)
o 16+ GB: Power users, multitasking, games, VM, etc.

RAM and Motherboard Compatibility

Component Must Match

RAM Type (DDR3/4/5) Motherboard slot type (e.g., DDR4 slot won't accept DDR3 RAM)

RAM Speed (MHz) Motherboard’s supported RAM frequency

RAM Capacity Max capacity and number of RAM slots on the board

Form factor Desktop uses DIMM; Laptops use SODIMM

Key Tip: Always check the motherboard specs (manual or manufacturer site) before
buying RAM!

Cooling & Stability

• RAM doesn't get hot like CPUs/GPUs, but high-performance RAM may have heat
spreaders for cooling.
 • ECC RAM (Error-Correcting Code RAM) is used in servers to automatically correct
memory errors.

Memory Slots & Installation Tips

• Always install RAM in matched pairs (if motherboard supports dual channel).
• RAM should click into place in the RAM slot.
• Use anti-static precautions when installing.

32-bit vs 64-bit Systems and RAM Limits

System Type Max RAM Supported

32-bit OS Up to 4 GB RAM

64-bit OS More than 4 GB (e.g., Windows 10 Home supports up to 128 GB)

Diagram: How RAM interacts with the CPU and

Storage
[Storage (SSD/HDD)]
↓ (Slower Access)
Load Program
↓
[RAM (Temporary Fast Memory)]
↑ Read/Write
↓
[CPU (Processes Instructions)]

Quick Recap Points

• RAM = short-term, fast-access memory.
• Volatile: data lost when power is off.
• DRAM, SDRAM, DDR = common types.
• Compatibility depends on DDR version, speed, and slot type.
• More RAM = better multitasking.
• Use 64-bit OS to fully utilize >4 GB RAM.
 Motherboards – Core Notes
What is a Motherboard?

• The main circuit board that connects and allows communication between all
components of a computer.
• Distributes power, data, and provides physical slots to install hardware like CPU,
RAM, and expansion cards.

Key Components

1. Chipset

• Controls data flow between CPU, RAM, storage, and peripherals.

• Originally split into:
o Northbridge – handles fast components: CPU, RAM, graphics card.
o Southbridge – handles slower devices: USB, hard drives, audio, etc.
• Modern CPUs integrate Northbridge into the CPU itself (e.g., Intel i-series, AMD
Ryzen).
2. Expansion Slots

• Enable upgrading or adding features like Wi-Fi cards, GPUs, sound cards.
• Standard today: PCIe (Peripheral Component Interconnect Express).
o Comes in different sizes: x1, x4, x8, x16.
o x16 is used for GPUs.

3. Form Factor

• Defines the physical size, layout, and mounting of the motherboard.

• Affects what case, power supply, and number of expansion slots you can use.

Type Description

ATX Standard size; lots of slots, ports

Micro-ATX Smaller; fewer slots

Mini-ITX Very compact; 1 expansion slot

 • Intel NUC and small PCs use Mini/Nano/Pico-ITX for ultra-compact builds.

Why This Matters for Job Roles

• RAM and CPU compatibility depends on motherboard socket and RAM slot type.
• Technicians must verify slot compatibility before replacing/upgrading hardware.
• Common interview Q: “Can you tell me what considerations are needed when
upgrading a motherboard?”

Physical Storage (Hard Drives)

1. Basic Data Units (Must Know)

Term Definition Analogy / Note

Think of it as a light switch
Bit Smallest unit; stores a 0 or 1
(on/off)
8 bits = 1 byte; holds a single letter or
Byte “A” = 01000001
symbol
Kilobyte (KB) ~1,000 bytes (1,024 bytes binary) Text files or icons
Megabyte
~1,000,000 bytes (1,048,576 binary) 1 minute of MP3 music
(MB)
Gigabyte (GB) ~1 billion bytes (1.07 billion binary) 300+ photos or 3 hrs of music
Terabyte (TB) ~1 trillion bytes (1.1 trillion binary) 200,000 songs or 300 hrs video

Binary vs Decimal:

• Binary (real): 1 KB = 1,024 bytes

• Decimal (marketed): 1 KB = 1,000 bytes
• Storage devices often advertise decimal sizes, but OS reads binary.
 • That's why your "500 GB" drive shows up as ~465 GB in Windows.

2. Hard Drive Types

Drive Type Key Characteristics Pros Cons

HDD (Hard Disk Spinning disk + mechanical Cheap, large Slow, fragile
Drive) arm capacity (moving parts)
SSD (Solid State No moving parts; stores on
Fast, durable, slim Expensive per GB
Drive) flash memory
Good speed + large Complex, middle-
Hybrid Drive SSD + HDD combined
storage cost

SSD = like a USB flash drive, but faster and internal

HDD = like a record player storing data

3. Interfaces (Connection Types)

Interface Used for Key Benefit

HDDs &
SATA (Serial ATA) Hot-swappable, widely used, decent speed
SSDs
NVMe (Non-Volatile Memory High-end Very high speed; plugs into motherboard
Express) SSDs directly (no cable)

NVMe SSDs use PCIe lanes → much faster than SATA SSDs
SATA = cable; NVMe = expansion slot
 4. RPM (Only for HDDs)

• RPM = Revolutions per Minute

• Common: 5400 RPM (slow), 7200 RPM (faster)
• Higher RPM → faster read/write speed → better performance

5. Storage Capacity Examples

Capacity Can Hold Approx.

1 GB 300 photos or 1 hour of video
500 GB 165,000 songs
1 TB 250,000 photos or 300 hours of HD video
1 PB 1.5 million CDs or ~500 billion text pages
 6. Real-world IT Relevance

✅ Common IT support tasks involving storage:

• Replacing/upgrading HDD to SSD

• Diagnosing slow PC due to HDD failure
• Explaining why a "500 GB" drive only shows 465 GB
• Connecting SATA/NVMe drives
• Backing up data before drive replacements
• Imaging OS onto SSDs

Power Supplies
Core Function

• Converts AC (Alternating Current) from the wall into DC (Direct Current) used
by computer components.
• AC changes direction; DC flows in one direction (needed for computer circuits).
• Ensures voltage is stepped down to safe, usable levels (e.g., 12V, 5V, 3.3V DC).

Key Electrical Concepts

Concept Meaning Analogy

Voltage (V) Electrical pressure; pushes electrons through a circuit Water pressure in a pipe
Flow rate of electricity (amperage); pulled by the Width of water pipe
Current (A)
device flow
 Concept Meaning Analogy
Wattage
Total power used = Voltage × Current Total water delivered
(W)

• Formula: Watts = Volts × Amps

• Devices pull current (amps) as needed. Supplying too much voltage can damage
them.
• Using higher wattage power supply is fine — system will only use what it needs.

Power Supply Components

• Fan – for internal cooling.

• Voltage label – printed on side; lists voltage, current, and wattage per rail.
• Cables – include:
o 24-pin ATX for motherboard
o 4/8-pin CPU power
o SATA power for drives
o PCIe power for GPUs
o Molex (older components)
• Power switch and power input socket

ATX power supply pinout diagram

 Computer power supply cables labeled

Voltage Compatibility

• North America: 110V–120V

• Europe/Asia: 220V–240V
• Plugging 120V device into 220V socket = damage (overvoltage)
• Plugging 220V device into 120V socket = underperformance (undervoltage)
• Use auto-switching or dual voltage power supplies for travel or international use

Common Wattage Requirements

Use Case Suggested PSU Wattage

Basic desktop / Office tasks 300–500W
Gaming PC 600–850W
Video editing / Rendering 750–1000W+

• Always choose a PSU with some headroom for future upgrades or spikes.

❗ Diagnosing Power Supply Issues

• Symptoms of bad PSU:

o PC won’t turn on
o Random shutdowns or reboots
o Burning smell or clicking sounds
o Components not receiving power
• Causes:
o Power surges
o Burnouts
o Lightning strikes
o Dust buildup blocking fan
• Tools to diagnose:
 o PSU tester (for checking voltage outputs)
o Multimeter (for voltage and continuity)
o Known-good PSU for swap testing

IT Support Skills Checklist (Must Know)

• Identify PSU type (ATX, SFX, etc.)

• Read PSU wattage and voltage labels
• Test PSU with multimeter or PSU tester
• Replace PSU safely (power off, unplug, ground yourself)
• Understand cable compatibility and routing
• Match PSU wattage to hardware requirements

Diagram: Basic PC Power Flow

[Wall Outlet (AC)]
↓
[Power Supply Unit (Converts to DC)]
↓
┌──────────────┬────────────┬───────────────┐
│ Motherboard │ Drives │ GPU / CPU │
└──────────────┴────────────┴───────────────┘

How to Adapt for Different Voltage Regions

Situation Solution

✅ Replace PSU with correct voltage unit

Imported PC with different voltage ✅ Use dual-voltage PSU with toggle switch
✅ Use external power converter

• Wrong voltage risks:

o 120V into 240V PSU → Burnout
o 240V into 120V PSU → Underpowered, won’t run properly

How to Choose a Power Supply (PSU)

✅ 1. Wall Socket Voltage (Input)

• Match PSU to local wall voltage

• Use dual-voltage PSU or converter when needed
✅ 2. Power Needs of Components
Type of Component Power Usage

Basic PC (Office use) 300–500W

High-end CPU / Gaming GPU 600–850W+

Multiple Drives, Rendering, etc. 750–1000W+

• More components = higher PSU wattage needed

✅ 3. Motherboard Form Factor

• ATX (most common) – standard 24-pin connector

• ITX (smaller systems) – may use compact PSUs
• Motherboard documentation lists PSU compatibility

PSU Output Voltages & Uses

Voltage Used By Components

3.3V DIMMs, chipsets, some PCI/AGP cards

5V Disk logic, SIMMs, ISA cards

12V Motors, fans, high-power voltage regulators

Voltage regulators on the motherboard distribute proper voltage to parts

PSU Connectors Overview (Image search: ATX PSU connectors diagram)

Connector Use

24-pin ATX (or 20+4) Main motherboard connector

8-pin CPU (EPS12V) CPU power (some are 4+4 pin)

6/8-pin PCIe Graphics card (GPU)

SATA Power SSDs, HDDs, optical drives

Molex Legacy devices (e.g., IDE drives)

Floppy (obsolete) Very old floppy disk drives

P4 (4-pin) Additional CPU/motherboard power (may combine into 8-pin)

 Note: Modern power supplies are modular, semi-modular, or non-modular, affecting
cable management and airflow.

Mobile Devices
What Are Mobile Devices?

• Portable computing devices powered primarily by batteries.

• Contain CPU, RAM, storage, display, power systems, peripherals—just like
desktops/laptops.
• Examples:
o General-purpose: Smartphones, tablets
o Task-specific: Smartwatches, fitness trackers, e-readers

Key Differences vs Desktops/Laptops

Feature Mobile Devices Desktops/Laptops

Portability High (battery powered, lightweight) Low to Medium

Component Design Highly integrated/soldered Modular, user-replaceable

Expandability Limited High (RAM, drives, GPUs, etc.)

Battery Built-in rechargeable Removable/External (laptops)

Integration & System on a Chip (SoC)

• Mobile devices are highly integrated (non-modular).

• Small devices use a System on a Chip (SoC):
o Combines CPU, GPU, RAM, sometimes storage on a single chip.
o Benefits: Smaller size, low power usage, improved efficiency

"Smartphone motherboard SoC"

 Peripherals in Mobile Devices

• Mobile devices use peripherals like:

o Bluetooth headphones
o Smart pens
o Game controllers
• Some devices are also peripherals:
o A fitness tracker → accessory to a smartphone
o Smartwatch → secondary screen for phone

Peripheral chains: Device can both connect to and act as a peripheral.

Connectors & Ports in Mobile Devices

🔧 Common Connector Types:

Connector Type Used For

USB-C Universal standard (charging + data)

Lightning Apple-only devices

Micro-USB Older Android devices

Mini-USB Rare, older peripherals

Micro-HDMI Small form display output (e.g., tablets)

Mini-HDMI Video output for small devices

Mini DisplayPort Display output for some tablets/laptops

Image search keywords: "Mobile device ports and connectors chart"

🔒 Why Use Proprietary Ports?

• Small/mobile designs need custom ports to improve:

o Waterproofing
o Size efficiency
o Durability
• Example: Waterproof fitness tracker may use magnetic charger instead of exposed
USB
 Mobile OS & Software

• Run mobile-optimized OS (Android, iOS, Wear OS, etc.)

• Apps and OS features focus on:
o Low power consumption
o Touchscreen UIs
o Background task efficiency
o Security features (sandboxing, app permissions)

Peripherals and Ports

What Are Peripherals?

• Peripheral: Any external device connected to a computer to add functionality.

• Examples:
o Input: Keyboard, mouse, scanner, joystick
o Output: Monitor, printer, speakers
o Input/Output: External drives, webcams, touchscreens
• Most peripherals connect via USB or display connectors (HDMI, DisplayPort, etc.).

USB (Universal Serial Bus) Connectors

USB Generations (Type-A ports)

Version Color (Typical) Speed Notes

USB 2.0 Black 480 Mbps (0.48 Gbps) Widely used for keyboards, mice
USB 3.0 Blue 5 Gbps Faster data transfer
USB 3.1 Teal 10 Gbps Used for modern external drives
USB4 USB-C only 40 Gbps Thunderbolt 3 compatible

• ✅ Backward Compatible: You can plug USB 2.0 into USB 3.0 ports, but the speed
matches the slower version.
• Speed Units Reminder:
o Mbps = megabits per second (data transfer speed)
o MB = megabytes (data size)
o ✅ 1 MB = 8 Mbps → To transfer 1MB/s, you need 8 Mbps bandwidth
 USB Connector Types

Connector Usage Notes

USB-A Standard rectangular connector Found on most PCs/laptops
Micro-USB Older smartphones, tablets, cameras Obsolete but still encountered
New standard (phones, laptops, Reversible, fast, carries data + video +
USB-C
peripherals) power
USB4 (USB- High-speed devices (monitors,
Uses Thunderbolt 3 protocol
C) docks)
Lightning Apple devices only Proprietary, carries power + data
 Display Connector Types
Connector Carries Audio? Notes
HDMI ✅ Yes Standard for TVs and monitors, carries both
DisplayPort ✅ Yes High-resolution displays; common in business
DVI ❌ No (usually) Older standard; video only
VGA ❌ No Very old analog standard
USB-C ✅ Yes Also used for display on some devices (Alt Mode)

Tip: If setting up a projector with audio, avoid DVI—use HDMI or DisplayPort instead.

Communication Connectors (Networking)

Connector Use Case Notes
RJ-45 Ethernet (LAN) 8-pin connector for network cables
RJ-11 Phone lines, modems (POTS/DSL) Smaller, 4-6 pins
F-type Cable internet Coaxial; used with cable modems
Fiber-optic High-speed backbone Used by ISPs, long-distance data

Legacy Device Connectors

Connector Use Notes
DB89 Old keyboards, joysticks Obsolete but still encountered sometimes
Molex Power to drives, fans Internal power connector (older desktops)
 Punch Down Blocks
• Terminal strip used to connect telephone or LAN cabling
• Wires are “punched down” into the terminals using a tool
• Still used in enterprise and telecom closets

What IT Support Pros Do With Peripherals

• Identify the correct port for input/output/peripheral devices
• Troubleshoot connectivity issues (e.g., faulty USB ports)
• Verify data speeds and compatibility
• Replace or reconfigure old legacy connectors
• Set up display devices for users
• Understand physical cable limitations and match with use case

✅ Key Takeaways
• USB is the most common connector type—know its versions, colors, speeds.
• USB-C and USB4 are replacing older standards for power + data + display.
• Display connectors vary—only HDMI, DisplayPort, and USB-C carry audio +
video.
• RJ-45 (Ethernet) and RJ-11 (Phone) are essential networking connectors.
• IT pros must recognize legacy connectors and know how to support them.
• Communication about speed (Mbps vs MB) is a frequent source of confusion—
clarify it.
 BIOS and UEFI

✅ What is BIOS?

• BIOS (Basic Input/Output System): Firmware that initializes and tests hardware at
startup.
• Stored on a ROM chip (non-volatile memory) on the motherboard.
• Loads the bootloader, which loads the Operating System (OS).

✅ What is UEFI?

• UEFI (Unified Extensible Firmware Interface): Modern replacement for traditional

BIOS.
• Supports larger hard drives, faster boot times, better UI, and more hardware
compatibility.
• Eventually replacing BIOS in most systems.

BIOS vs UEFI interface

BIOS Roles & Functions

• Power-On Self Test (POST): Hardware check when computer starts.

o Errors are reported via beep codes.
o A single beep usually means "all OK".
o Multiple beeps mean hardware issues (refer to motherboard manual).
• Loads drivers for basic hardware (keyboard, mouse, display).
• Helps CPU communicate with external devices before the OS loads.
CMOS Chip

• CMOS = Complementary Metal-Oxide Semiconductor.

• Stores BIOS settings (e.g., date/time, boot order).
• Can be accessed during boot (common keys: DEL, F2, ESC, F10, etc.).
• Battery-powered to retain settings when the PC is off.

BIOS Settings in IT Support

• BIOS settings control:

o Boot device priority (e.g., boot from USB/CD/Network).
o Hardware settings (enabling/disabling devices).
o System security features (BIOS password, Secure Boot).
• Reimaging requires:
o Booting from external media (USB/CD/network server).
o Changing boot order in BIOS.

Drivers

• Small programs that let CPU communicate with hardware.

• Loaded from hard drive after BIOS finishes basic initialization.
• Example: Keyboard input → driver translates key press into CPU-readable data.

Beep Codes (POST Errors)

• No display? Look for beep codes:

o 1 beep = success.
o 2+ beeps = error (varies by manufacturer).
o No beep: system may lack built-in speaker or power issue.
 Installing the Processor (CPU) – Step-by-Step Guide

✅ Static Electricity Protection (ESD)

• ESD (Electrostatic Discharge) can damage computer components.

• Two protection methods:
o Touch grounded metal (e.g., plugged-in power supply) every few minutes.
o Wear an anti-static wrist strap, clip it to unpainted metal (e.g., PC case).
• Components come in anti-static bags—keep parts inside until use.

Step 1: Prepare the Motherboard

• Match the form factor (e.g., ATX) of the motherboard to the case.
• Align screw holes in motherboard with case holes.
• Install or check for standoffs (pre-installed in some cases); they prevent short circuits
by raising the board from the case surface.

Step 2: Install the CPU (Central Processing Unit)

• Handle the CPU carefully—very expensive & delicate pins.

• Make sure:
o CPU type matches socket type (e.g., LGA CPU with LGA motherboard
socket).
o Align corner markers (often a small triangle) on CPU and socket.
• Insert CPU into socket gently, then lock it down using the latch/retention
mechanism.

Step 3: Apply Thermal Paste

• Thermal paste improves heat transfer between CPU and heat sink.
• Apply a small dab in the center of the CPU (pea-sized).
• Spread it evenly (optional: cross pattern or line method).
• Avoid using too much—can cause spillage and poor contact.

Step 4: Install the Heat Sink / CPU Cooler

• Align cooler with the mounting holes on the motherboard.

• Use even pressure to avoid cracking CPU or uneven thermal paste spread.
• Tighten screws in a diagonal pattern (e.g., top-left then bottom-right).
• Re-check all screws for tightness.
 Step 5: Connect CPU Cooler to Motherboard

• Plug the cooler's fan cable (usually a 4-pin PWM or 3-pin) into the CPU_FAN
header on the motherboard.
• This allows the motherboard to control the fan speed based on temperature.

Pro Tips

• Heat sinks vary in size—ensure compatibility with case clearance.

• Stock coolers usually come pre-applied with thermal paste.
• Reapplying thermal paste is necessary if removing and reinstalling the cooler.

IT Support Interview Angle

• Be able to explain:
o Why thermal paste is necessary
o The function of CPU fan headers
o How to avoid ESD damage
o Why correct CPU alignment and socket type matter
• Useful task during desktop repair, rebuilds, or reimaging setups.

Link for step by step video:

CPU Installation

Adding RAM, SSD, Case Fan, and Power Supply – PC Assembly

Step 1: Install RAM (Memory)

• Locate DIMM slots on motherboard.

• Match RAM type to motherboard (e.g., DDR3, DDR4, DDR5).
• Check the notch on the RAM stick and slot—prevents incorrect insertion.
• Align carefully to avoid damaging the pins.
• Insert RAM stick firmly until you hear a “click” on both sides.
• Use color-coded slots for dual-channel mode:
o Usually insert in same-colored slots first (e.g., white slots).
o Refer to motherboard manual for correct slot population.
🧠 IT Interview Tip

• Be ready to explain dual-channel memory: it doubles bandwidth when identical

RAM sticks are installed in paired slots.
• Know how to identify RAM form factors: DIMM (desktop) vs. SO-DIMM
(laptops).

Step 2: Install SSD (Solid State Drive)

• SSD used: 2.5" SATA SSD (not M.2/NVMe).

• Mount SSD into drive cage or tray (slides or screws depending on case).
• Connect:
o SATA data cable from SSD → motherboard SATA port.
o SATA power cable from power supply → SSD power port.
• SATA cables are keyed to fit only one way.

🧠 IT Interview Tip

• Differentiate between:
o SATA SSD (slower, 2.5-inch form factor)
o NVMe M.2 SSD (faster, uses PCIe bus)
• SATA SSDs use AHCI protocol, NVMe uses NVMe protocol for faster
performance.

Step 3: Install Case Fan

• Case fans help with airflow and cooling components.

• Mount fan in proper position:
o Front/side fan = intake (pull cool air in)
o Rear/top fan = exhaust (push hot air out)
• Connect fan to:
o Motherboard fan header (labelled SYS_FAN or REAR_FAN)
o Or use Molex connector to power supply if motherboard header unavailable

🔁 Best Practice: Wind Tunnel Design

• Create a smooth airflow path:

o Intake → over CPU/GPU → out back/top.
o Prevents heat pockets inside the case.
 Step 4: Install Power Supply Unit (PSU)

• Insert PSU into case (typically bottom-rear).

• Orient fan facing down (if case has bottom ventilation).
• Secure PSU with screws at the back of the case.
• Route PSU cables to avoid contact with motherboard/components.
• Some builds allow installing PSU before motherboard, depending on case design.

🧠 IT Interview Tip

• Know the difference between modular, semi-modular, and non-modular PSUs.

• Modular PSUs reduce clutter and improve airflow.

Key Power Cables to Know (Connect Later)

• 24-pin ATX (motherboard power)

• 8-pin EPS (CPU power)
• 6/8-pin PCIe (graphics card power, if needed)
• SATA power (drives)
• Molex (older peripherals/fans)

Link for Step by Step video

Installing RAM, SSD, PSU

Step-by-Step: Final PC Assembly (GPU, Power,

Peripherals, Boot Test)
Step 1: Connect Power Supply to Components

1. Motherboard Main Power (24-pin ATX)

• Connect large 24-pin connector from PSU to motherboard.

• Supplies power to the motherboard and chipset.
• Only fits one way due to keyed connector.

2. CPU Power (4/8-pin EPS)

• Connect EPS connector (4+4 or 8-pin) to CPU power socket (usually top-left of
motherboard).
• Tight space—may require pressure.
• This powers the CPU voltage regulator module (VRM).
 Step 2: Install Graphics Card (GPU)

1. Locate PCIe x16 Slot

• Usually the topmost long PCIe slot closest to the CPU.

• Used for discrete graphics cards.

2. Insert the GPU

• Align with slot, press down until it clicks.

• Secure to case with screws or case latches.
• Connect PCIe power connectors (6-pin, 8-pin, or both) from PSU if GPU requires it.

3. Display Output

• GPU ports: HDMI, DisplayPort, DVI

• Plug monitor into GPU ports, not motherboard if GPU is installed.

Step 3: Connect Case Front Panel Cables

Front Panel Connectors:

• Power Switch, Reset Switch

• Power LED, HDD LED
• Front USB (2.0/3.0), Audio
• Pins labeled on motherboard: refer to motherboard manual for exact layout.

Tip: Some motherboards include a front panel block/adapter to simplify this process.

Step 4: Connect Peripherals

Peripheral Connection Type

Keyboard USB (wired/wireless dongle)

Mouse USB

Monitor HDMI / DisplayPort / DVI

Speakers 3.5mm jack or USB

• Plug into rear or top-panel USB ports.

• For DisplayPort, connect from GPU → Monitor.
 Step 5: Final Boot & Test

What to Check:

• Press power button.

• Check for:
o Fans spinning
o Motherboard lights
o Monitor signal ("No signal" = check GPU/monitor cable)
• If no display:
o Recheck: RAM seating, power cables, GPU, monitor input

Troubleshooting Boot Issues

Symptom Likely Issue

No power at all PSU switch off, bad wall socket, loose cable

Fans spin, no display RAM not seated, GPU loose, CPU not connected

“No boot device found” OS not installed, drive unrecognized

Beep codes or flashing LEDs Refer to motherboard manual for diagnosis

IT Support & Interview-Relevant Concepts

• Molex vs SATA Power:

o Molex: legacy 4-pin for fans, old drives.
o SATA Power: standard for SSDs/HDDs.
o Adapters exist but direct SATA preferred.
• PSU Wattage:
o Ensure enough wattage (esp. with GPU).
o Use online calculators like OuterVision.
• DisplayPorts vs HDMI:
o DisplayPort: preferred for higher refresh rates and daisy-chaining.
o HDMI: common and widely compatible.

Link for step by step video

GPU, Power, Peripherals, Boot Test

Glossary terms from course 1, module 2
Address bus: Connects the CPU to the MCC and sends over the location of the data, but not the data
itself
ATA: The most common interface that hard drives use to connect to our system
ATX (Advanced Technology eXtended): The most common form factor for motherboards
Backward compatible: It means older hardware works with newer hardware
Bios (Basic Input Output Services): The BIOS is software that helps initialize the hardware in our
computer and gets our operating system up and running
BYOD (Bring Your Own Device): Refers to the practice of allowing people to use their own personal
devices for work
Cache: The assigned stored location for recently or frequently accessed data; on a mobile app it is
where anything that was changed or created with that app is stored
Charge cycle: One full charge and discharge of a battery
Chipset: It decides how components talk to each other on our machine
Clock cycle: When you send a voltage to the clock wire
Clock speed: The maximum number of clock cycles that it can handle in a set in a certain time period
Clock wire: When you send or receive data, it sends a voltage to that clock wire to let the CPU know
it can start doing calculations
CPU: Central processing unit
CPU sockets: A CPU socket is a series of pins that connect a CPU’s processor to the PC’s
motherboard
Data sizes: Metrics that refer to data sizes including bit, byte, kilobyte, kibibyte, and megabyte
DDR SDRAM (Double Data Rate SDRAM): A type of RAM that is faster, takes up less power, and has
a larger capacity than earlier SDRAM versions
Desktop: The main screen where we can navigate our files, folders, and applications
DIMM: Dual Inline Memory Module
Display port: Port which also outputs audio and video
DRAM: Dynamic Random Access Memory
Drivers: The drivers contain the instructions our CPU needs to understand external devices like
keyboards, webcams, printers
DVI: DVI cables generally just output video
Electrostatic discharge: Electrostatic discharge is a sudden and momentary flow of electric current
between two electrically charged objects caused by contact, an electrical short or dielectric
breakdown
External Data Bus (EDB): It's a row of wires that interconnect the parts of our computer
Factory reset: Resetting a device to the settings it came with from the factory
Form factor: A mathematical way to compensate for irregularities in the shape of an object by using
a ratio between its volume and height
Hard drive: It is a long term memory component that holds all of our data, which can include music,
pictures, applications
Hardware: External or internal devices and equipment that help you perform major functions
HDD (Hard disk drive): Hard disk drives, or HDDs, use a spinning platter and a mechanical arm to
read and write information
HDMI: A type of cable that outputs both video and audio
Heatsink: It is used to dissipate heat from our CPU
Instruction set: A list of instructions that our CPU is able to run
ITX (Information Technology eXtended): A form factor for motherboards that is much smaller than
ATX boards
Land Grid Array (LGA): It is a type of CPU socket that stick out of the motherboard
Lightning adaptor: One of the standard power, data and display connector types used in mobile
devices
Mb/s: megabit per second, which is a unit of data transfer rate
Memory controller chip (MCC): A bridge between the CPU and the RAM
Micro display port: One of the standard power, data and display connector types used in mobile
devices
Micro HDMI: One of the standard power, data and display connector types used in mobile devices
Micro USB: One of the standard power, data and display connector types used in mobile devices
Mini HDMI: One of the standard power, data and display connector types used in mobile devices
Mini USB: One of the standard power, data and display connector types used in mobile devices
Motherboard: The body or circulatory system of the computer that connects all the pieces together
Northbridge: interconnects stuff like RAM and video cards
NVMe (NVM Express): interface standard which allows greater throughput of data and increased
efficiency
Overclocking: it increases the rate of your CPU clock cycles in order to perform more tasks
PCI Express: Peripheral Component Interconnect Express
Peripherals: the external devices which we connect to our computer that add functionality, like: a
mouse, a keyboard, and a monitor
Pin Grid Array (PGA): CPU socket where the pins are located on the processor itself
Ports: Connection points that we can connect devices to that extend the functionality of our
computer
POST (Power On Self Test): It figures out what hardware is on the computer
Power supply: Converts electricity from our wall outlet onto a format that our computer can use
Programs: Basic instructions that tell the computer what to do
RAM: Random Access Memory
Registers: An accessible location for storing the data that our CPU works with
Reimaging: The process of reimaging involves wiping and reinstalling an operating system using a
disk image which is a copy of an operating system
Return merchandise authorization (RMA): The process of receiving returned merchandise and
authorizing a refund
ROM chip (Read Only Memory): A read-only memory chip where the BIOS is stored
RPM: Revolutions per minute
Safe operating temperature: The temperature range in which rechargeable batteries must be kept
in order to avoid damage
SATA: The most popular serial ATA drive, which uses one cable for data transfers
SDRAM: It stands for Synchronous DRAM, this type of RAM is synchronized to our systems' clock
speed allowing quicker processing of data
SOC (System On a Chip): Packs the CPU, Ram, and sometimes even the storage onto a single chip
Southbridge: It maintains our IO or input/output controllers, like hard drives and USB devices that
input and output data
SSD: Solid State Drive
Standoffs: Used to raise and attach your motherboard to the case
Thermal paste: A substance used to better connect our CPU and heat sink, so the heat transfers
from to the other better
Type-C connector: A type of USB connector meant to replace many peripheral connections
UEFI: Unified Extensible Firmware Interface
USB (Universal Serial Bus): A connection standard for connecting peripherals to devices such as
computers
USB-C adapter: One of the standard power, data and display connector types used in mobile devices