If your Windows 10/11 PC shows 100% CPU usage, you will experience lag, stutters, freezes, and slow performance. This is one of the most common problems in Windows, especially on low-end and mid-range PCs.

In this guide, you’ll learn why the CPU goes to 100%, how to find the cause, and how to fix it permanently using simple methods.

⭐ Why Does CPU Usage Go to 100%?

Common reasons include:
  • Background apps running

  • Windows services stuck

  • Malware or unwanted processes

  • Heavy startup programs

  • Windows Update bugs

  • Game anti-cheat services

  • Driver issues

Let’s fix this step by step.

Method 1: Disable Background Apps

  1. Press Windows + I

  2. Go to Apps → Installed Apps

  3. Disable unnecessary apps running in background

  4. Remove unwanted software

🔹 This reduces CPU usage by 10–20%.

Method 2: Disable “SysMain” (Superfetch)

This service causes 100% CPU on many PCs.
  1. Press Windows + R

  2. Type: services.msc

  3. Find SysMain

  4. Right-click → Stop

  5. Set Startup type → Disabled


Method 3: Disable Windows Search Indexing

  1. Go to services.msc

  2. Find Windows Search

  3. Right-click → Stop

  4. Set Startup type → Disabled

This fix is highly effective on HDD systems.

Method 4: End High-Usage Tasks

  1. Press CTRL + SHIFT + ESC

  2. Open Task Manager

  3. Check CPU column

  4. End tasks using too much CPU (EXCEPT system tasks)

Common culprits:
  • Google Chrome

  • GameLauncher.exe

  • Update.exe

  • RuntimeBroker


Method 5: Disable Startup Programs

  1. Open Task Manager

  2. Go to Startup Apps

  3. Disable everything unnecessary
    (Spotify, Epic, Steam auto-start, Discord, etc.)


Method 6: Update / Reinstall Drivers

Outdated drivers cause CPU spikes.
Use:
  • AMD Adrenalin

  • NVIDIA GeForce Experience

  • Intel Driver Support Assistant

Always keep chipset drivers updated.

Method 7: Scan for Malware

  1. Open Windows Security

  2. Go to Virus & Threat Protection

  3. Full Scan

Optional (Better): Use Malwarebytes Free.


Method 8: Reset Windows Update Components

If Windows Update is stuck:
  1. Open CMD as Administrator

  2. Copy & paste:

    net stop wuauserv
    net stop bits
    net stop cryptsvc
    ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
    ren C:\Windows\System32\catroot2 catroot2.old
    net start wuauserv
    net start bits
    net start cryptsvc

This fixes update loops that cause high CPU.


⭐ Bonus: Best Power Settings

  1. Go to Control Panel → Power Options

  2. Select High Performance

This stabilizes CPU usage.

🟢 Conclusion

High CPU usage is one of the most annoying issues in Windows 10/11, but following the steps above will reduce CPU spikes and make your PC run smoother instantly.
If the issue continues, your CPU may be:
  • Overheating

  • Thermal throttling

  • Or the PC needs simple cleanup & cooling

Comment below if you need a custom fix for your PC specs!