Self HelpBoise Computer Care

Desktop & PC hardware

When to replace thermal paste

Does your PC need new thermal paste? How to check CPU temps, why dust is first, and how to repaste a desktop safely.

Difficulty
Advanced
Time
30-60 min
Steps
5
Updated

Sounds like this?

  • CPU temperatures higher than when new
  • Fans ramp up quickly
  • PC is 3-5+ years old
  • Throttling during games or rendering

Step by step

  1. Measure first: check CPU temperature at idle and under load with HWiNFO or your maker's tool. Most desktop CPUs idle around 30-50°C; sustained 90°C+ under load is high for many models.
  2. Clean dust first. Dust causes more heat problems than old paste.
  3. If temps are still high on a PC that's several years old, repasting may help.
  4. Remove the cooler, wipe off old paste with isopropyl alcohol, apply a pea-sized amount in the center, and reinstall the cooler evenly in a cross pattern.
  5. Re-check temperatures.

Related error codes & messages

Quick answers

When should I stop and get professional help with "When to replace thermal paste"?

Stop and get help if: You aren't comfortable removing a CPU cooler. It's a laptop or a Mac. Temperatures don't improve after cleaning and repaste (the cooler or pump may be failing). Boise Computer Care can diagnose it for a $60 fee; call 208-996-3508.

How long does this fix take and how hard is it?

Plan on 30-60 min. Difficulty: Advanced.

Is it safe to try this myself?

Mostly, if you follow these precautions: Use isopropyl alcohol 90%+ and a lint-free cloth to clean old paste. Don't use liquid metal unless you're experienced; it's electrically conductive. Laptops often require full disassembly. Leave those to a technician.

Which error messages or codes does this guide cover?

CPU over temperature error, Thermal throttling.

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