Computer Hardware

Week of 2026-08-25 · Download .docx

Objectives

Identify types and functions of RAM, storage devices, and common memory form factors.
Describe common I/O peripherals including displays, printers, and USB connectors.
Explain CPU components including clock speed, cores, cache, and sockets.
Identify power supply components, cooling systems, and safe-handling practices.

Key terms

CPU: Central Processing Unit — fetches, decodes, and executes all program instructions.
GHz: Gigahertz — one billion clock cycles per second; measures CPU speed.
RAM: Random Access Memory — volatile, fast temporary storage that loses data when power is removed.
DDR5: Double Data Rate 5 — the current generation of desktop DIMM memory standard.
NVMe: Non-Volatile Memory Express — a high-speed SSD interface using PCIe lanes (3–7 GB/s).
SATA III: Serial ATA III — 6 Gbps interface used for traditional HDDs and budget SSDs.
PSU: Power Supply Unit — converts AC wall power to DC rails (+12V, +5V, +3.3V).
POST: Power-On Self-Test — hardware diagnostic run by UEFI/BIOS before the OS loads.
Thermal paste: Thermally conductive compound applied between CPU and heatsink to fill microscopic air gaps.
ESD: Electrostatic Discharge — invisible static spark that can destroy chips; prevent with anti-static wrist strap.
UEFI: Unified Extensible Firmware Interface — modern replacement for BIOS that initializes hardware and boots the OS.
USB 3.2 Gen 1: USB standard delivering 5 Gbps throughput (formerly USB 3.0 / SuperSpeed).
IPS: In-Plane Switching — LCD panel technology with 178° viewing angles and accurate color.
KVM switch: Keyboard-Video-Mouse switch — lets one set of peripherals control multiple computers.
CMOS battery: Small coin cell (CR2032) that keeps BIOS settings and the real-time clock alive when main power is off.

The concept

Computer hardware is the physical foundation of every digital system. The CPU is the brain — it fetches an instruction from memory, decodes what operation it requires, executes the operation, and stores the result. Modern CPUs contain multiple cores (quad-core = 4, octa-core = 8), each capable of running a separate thread simultaneously. Cache memory (L1/L2/L3) sits on the CPU die and stores copies of frequently used data so the processor does not wait for slower RAM on every access.

RAM (Random Access Memory) provides the CPU with a fast working space. It is volatile: remove power and all data disappears. DDR5 DIMMs are the current desktop standard; SO-DIMMs are the smaller laptop form factor. Installing two identical sticks in matching color-coded slots enables dual-channel mode, doubling memory bandwidth.

Storage is non-volatile. NVMe SSDs plug into M.2 slots and use PCIe lanes for speeds up to 7 GB/s. SATA SSDs and HDDs use the older SATA III interface capped at 600 MB/s. HDDs store data on spinning magnetic platters and are slower but cost less per gigabyte. Choosing the right storage means balancing speed, capacity, and budget.

The Power Supply Unit (PSU) converts 120V AC from the wall into DC rails that every component requires. The +12V rail powers the CPU and GPU; +5V and +3.3V serve chipsets, USB, and RAM. Total PSU wattage must exceed the peak draw of all installed components, with 20% headroom recommended. A UPS (Uninterruptible Power Supply) adds a battery that keeps the system running through brief outages and protects against voltage surges.

Every time the computer starts, the UEFI/BIOS firmware runs POST — it checks that the CPU, RAM, and storage are present and functional. If POST passes, UEFI hands control to the bootloader, which loads the operating system. If POST fails, you hear beep codes or see on-screen error codes identifying the faulty component.

Proper cooling prevents permanent damage. Thermal paste fills the microscopic valleys between the CPU heat spreader and heatsink base. Case fans should be arranged for front-to-back airflow: intake at front/bottom, exhaust at rear/top. The motherboard controls fan speed via PWM signals based on temperature sensor readings.

Safe handling requires an anti-static wrist strap grounded to the case chassis. Electrostatic discharge invisible to the eye can permanently destroy CPUs, RAM, and GPUs with a single spark.

Worked examples

Example 1: You open a gaming PC and see two RAM sticks installed in slots A1 and B1. The user complains of low memory speed. You check the manual — dual-channel requires slots A2 and B2 (the two slots of matching color). You move the sticks to the correct paired slots, reboot, and dual-channel shows up in BIOS memory info, confirming the fix.

Example 2: A workstation powers on, fans spin briefly, then shuts off. POST never completes. You remove the GPU and reseat it. No change. You check the PSU label: 550W, but a GPU calculator shows the build needs 620W under load. You replace the PSU with an 850W unit, the system posts and boots normally — PSU wattage was insufficient.

Common mistakes

Confusing RAM capacity (GB) with speed (MHz/MT/s) — they are independent specifications.
Installing RAM in non-paired slots and wondering why dual-channel mode does not activate.
Applying too much or too little thermal paste — a pea-sized dot in the center is correct for most CPUs.
Forgetting the anti-static wrist strap before touching bare PCBs or chips.
Underestimating PSU wattage — always calculate the peak system draw and add 20% headroom.

Self-check

Try each one before you look. A miss here costs nothing and tells you exactly what to reread.

1. Which voltage rail of an ATX PSU powers the CPU and GPU?

2. What prevents ESD damage when handling components?

3. A computer beeps at startup and never shows video. What is the most likely cause?

4. What interface does an NVMe SSD use?

5. What is the purpose of CPU cache?

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