CPU Architecture & Processors

CompTIA A+ Core 1 (220-1101) • Domain 3.0 Hardware

Key Concepts: CPU Sockets Cores & Threads Cache Levels Clock Speed Thermal Design

What is a CPU?

The Central Processing Unit (CPU) is the "brain" of the computer. It executes instructions from programs by performing basic arithmetic, logic, controlling, and input/output operations.

A+ Exam Tip: Know the difference between Intel and AMD socket types, and understand that CPUs are NOT interchangeable between different socket types.

CPU Specifications

Clock Speed

Measured in GHz (gigahertz) - the number of cycles per second.

Base Clock: Standard operating speed
Turbo/Boost: Maximum speed under load
Higher isn't always better - efficiency matters!

Cores & Threads

Cores = Physical processing units

Threads = Virtual cores (via Hyper-Threading/SMT)

Dual-core = 2 cores
Quad-core = 4 cores
A 4-core/8-thread CPU can handle 8 tasks simultaneously

CPU Cache Levels

Cache Level	Size	Speed	Location
L1 Cache	32-64 KB per core	Fastest	Inside each core
L2 Cache	256 KB - 1 MB per core	Fast	Dedicated per core
L3 Cache	8-64 MB shared	Slower	Shared across all cores

Memory Hierarchy: L1 → L2 → L3 → RAM → Storage (fastest to slowest)

CPU Socket Types

Intel Sockets

Socket	CPUs
LGA 1700	12th-14th Gen Core (Alder Lake+)
LGA 1200	10th-11th Gen Core
LGA 1151	6th-9th Gen Core
LGA 2066	Core X-Series (HEDT)

AMD Sockets

Socket	CPUs
AM5	Ryzen 7000 Series
AM4	Ryzen 1000-5000 Series
TR4/TRX40	Threadripper (HEDT)
SP3	EPYC (Server)

Thermal Design Power (TDP)

TDP measures the maximum heat a CPU generates under load (in watts). This determines cooling requirements.

          Low TDP (15-35W)

          Laptops, ultrabooks

          U/P-series chips

          Standard TDP (65W)

          Desktop, mainstream

          Non-K Intel, Ryzen

          High TDP (95-125W+)

          Enthusiast, workstation

          K-series, X-series

CPU Architecture Types

Architecture	Bit Width	Max RAM	Use Case
x86 (32-bit)	32-bit	4 GB	Legacy systems, older software
x64 (64-bit)	64-bit	16+ EB (theoretically)	Modern desktops, servers
ARM	32/64-bit	Varies	Mobile, tablets, Apple Silicon

Knowledge Check

Q1: A CPU has 6 cores with Hyper-Threading enabled. How many threads can it handle?

Q2: Which cache level is the fastest but smallest?

Q3: What socket does an AMD Ryzen 5000 series CPU use?