Chromebook & Linux

Linux computer running hot with high CPU usage

Sustained high CPU usage from an unclear source is usually a runaway process or background update, not a hardware fault. Identifying and stopping the process resolves it immediately.

Difficulty
Intermediate
Time
15–40 minutes
DIY cost
$0–$15
Pro cost
$70–$130

Symptoms

  • Fan runs constantly at high speed
  • System feels sluggish across all apps
  • CPU usage shows near 100% in system monitor
  • Laptop feels hot to the touch

Likely causes

  • CommonA runaway or stuck application processA crashed but still-running process can consume a full CPU core indefinitely.
  • CommonBackground system update or indexingSearch indexing or package updates can spike CPU temporarily.
  • PossibleMalware or cryptomining scriptUnusual processes with random names using high CPU can indicate compromise.
  • PossibleDust-clogged cooling reducing efficiencyPoor cooling makes the CPU work harder and throttle more under normal loads.

What to do

  1. Open a system monitor (System Monitor GUI or 'top'/'htop' in terminal) and sort by CPU usage.
  2. Identify the top process; if it's an app you recognize acting up, close it normally first.
  3. If a process won't close, end it with 'kill [PID]' or 'kill -9 [PID]' as a last resort.
  4. Check if the usage returns after ending it, which points to something relaunching it automatically.
  5. Search the process name online if unfamiliar, since some legitimate system processes have unclear names.
  6. If usage stays high with no clear cause, run an antivirus/rootkit scan (like ClamAV or rkhunter) as a precaution.
  7. Clean dust from vents and fans if the machine runs hot even at idle.

Tools and parts

  • Compressed air can (for dust)

When to call a pro

If a scan finds malware you can't remove, or the machine runs hot even after cleaning, a technician can help.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.