The CPU
Week 3 · Module 3: The CPU · Download .docx
Objectives
- Identify Intel (LGA) and AMD (PGA/AM4) socket types
- Explain TDP, cache hierarchy, and clock speed
- Perform correct CPU installation and thermal paste application
- Interpret common CPU troubleshooting symptoms
Key terms
- LGA
- Land Grid Array — motherboard has the pins; CPU has flat pads (Intel desktop).
- PGA
- Pin Grid Array — CPU has the pins; socket has holes (AMD AM4).
- TDP
- Thermal Design Power — max sustained watts of heat the cooler must dissipate.
- L1 Cache
- Fastest per-core cache (~256 KB); lowest latency, built into each core.
- Thermal paste
- Compound filling microscopic gaps between CPU IHS and cooler base.
The concept
The CPU fetches instructions from RAM, decodes them, executes operations, and writes results back. Modern CPUs have multiple cores — each capable of independent execution — plus SMT (Hyper-Threading on Intel), which presents two logical threads per physical core. Cache levels store frequently used data close to execution: L1 is fastest (per-core, ~256 KB), L2 is mid-tier (per-core, ~1-4 MB), L3 is shared (16-64 MB). TDP tells you the minimum cooler capacity in watts. Thermal paste eliminates air gaps between the CPU's heat spreader and the cooler base — air is a poor thermal conductor.
Worked examples
Common mistakes
- Too much thermal paste — excess spreads into the socket and can short contacts.
- Pressing an LGA CPU with force — the pins are on the board; pressure bends them.
- Forgetting the fan header — the CPU throttles immediately from overheating at boot.
Self-check
Try each one before you look. A miss here costs nothing and tells you exactly what to reread.
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