High CPU usage can slow down your computer, make fans spin loudly, and drain your battery faster than usual. Whether you’re using macOS or Windows, this issue often comes from background apps, system processes, or software bugs. In this 2025 guide, we’ll walk through how to identify the cause and fix high CPU usage step by step — no tech degree required.
What Causes High CPU Usage?
Your CPU (Central Processing Unit) is like your computer’s brain. When it’s overworked, your system becomes sluggish or unresponsive. Common reasons for high CPU usage include:
- Too many background apps running at once
- Browser tabs using excessive resources
- Outdated software or drivers
- Malware or unwanted programs
- System processes stuck in a loop
- Poorly optimized startup programs
Step 1: Check What’s Using CPU Resources
On Windows
- Press Ctrl + Shift + Esc to open Task Manager.
- Click the Processes tab and sort by CPU to see what’s consuming the most power.
- Identify any app or background process that’s using a high percentage of CPU (e.g., over 80%).
On macOS
- Open Activity Monitor (Finder → Applications → Utilities → Activity Monitor).
- Click the CPU tab.
- Sort by the % CPU column to identify which apps are consuming the most resources.
Once identified, you can decide whether to close or uninstall the problematic program.
Step 2: Restart and Update Your System
A simple restart can solve temporary process loops or memory leaks. After restarting, ensure your system is updated.
On Windows
- Go to Settings → Windows Update → Check for updates.
On macOS
- Open System Settings → General → Software Update.
Updates often fix CPU spikes caused by bugs or incompatible background services.
Step 3: Disable Unnecessary Startup Programs
Too many apps launching at startup can cause constant high CPU usage.
On Windows
- Open Task Manager → Startup apps.
- Disable programs you don’t need to run automatically.
On macOS
- Open System Settings → General → Login Items.
- Review the list and remove unnecessary apps.
Step 4: Scan for Malware or Adware
Malware can silently consume CPU power. Even modern systems like Windows 11 and macOS Ventura aren’t immune.
- Windows: Use Microsoft Defender or a trusted tool like Malwarebytes Free.
- macOS: Try Malwarebytes for Mac or Bitdefender Virus Scanner.
Run a full system scan and remove any detected threats.
Step 5: Manage Browser Tabs and Extensions
Modern browsers like Chrome, Edge, and Safari are notorious for eating CPU cycles.
- Limit the number of tabs open.
- Disable or remove unnecessary extensions.
- Use Task Manager inside Chrome (
Shift + Esc) to identify high-usage extensions or pages. - Try lighter browsers such as Brave or Firefox, which are better optimized for CPU efficiency.
Step 6: Reset Power and Performance Settings
On Windows
- Go to Control Panel → Power Options.
- Choose Balanced or Power Saver mode instead of High Performance.
- Optional: Use Windows Performance Troubleshooter to auto-detect issues.
On macOS
- Go to System Settings → Battery → Options.
- Set Low Power Mode when not performing heavy tasks.
Step 7: Check for Background Services and Updates
Some apps (like Adobe Creative Cloud, OneDrive, or iCloud) constantly sync in the background.
- Pause or disable sync when not needed.
- Open each app’s preferences and disable auto-start or auto-sync options.
Also, background system updates (Windows Update, Spotlight indexing, Time Machine backups) can cause short-term spikes — let them finish before troubleshooting further.
Step 8: Reset or Reinstall Problematic Apps
If a specific app is always topping your CPU list, it may be corrupted. Try reinstalling it:
- Uninstall the app completely.
- Restart your system.
- Reinstall the latest version from the official website or App Store.
Apps like Zoom, Dropbox, or Chrome occasionally misbehave after updates, so reinstalling helps restore normal behavior.
Step 9: Free Up Disk Space and Clear Cache
A nearly full disk can make your CPU work harder, especially on macOS with Spotlight indexing.
- Delete unused files and empty your Trash or Recycle Bin.
- Use built-in tools:
- macOS: About This Mac → Storage → Manage.
- Windows: Settings → Storage → Temporary Files → Clean up now.
- You can also use trusted utilities like CCleaner (Windows) or CleanMyMac X (macOS) to safely clear caches.
Step 10: Consider Hardware Upgrades
If you’ve optimized everything and still face high CPU usage, your hardware may simply be outdated.
- Add more RAM if your system constantly runs near full capacity.
- Upgrade to SSD storage for faster load times.
- If you’re using an older laptop (pre-2018), consider upgrading to a newer model optimized for modern software.
Pro Tips to Keep CPU Usage Low
- Restart your device weekly to refresh system memory.
- Keep apps updated and uninstall unused software.
- Avoid running multiple antivirus programs simultaneously.
- Turn off animations and visual effects in Windows or macOS for a performance boost.
- Regularly monitor CPU temperature using tools like HWMonitor (Windows) or iStat Menus (macOS).
Final Thoughts
Fixing high CPU usage on Windows and macOS doesn’t have to be complicated. Start by identifying the culprit through Task Manager or Activity Monitor, clean up startup apps, and keep your system updated. Regular maintenance, malware scans, and mindful browsing habits can dramatically improve your computer’s speed and longevity in 2025.
FAQ
Why is my CPU usage always high even when idle?
It could be due to background apps, Windows Update, or malware. Check Task Manager or Activity Monitor for hidden processes.
Is 100% CPU usage bad?
Temporary spikes are fine, but constant 100% usage may cause overheating or slowdowns.
Will adding more RAM reduce CPU usage?
Indirectly, yes. More RAM helps your system handle multitasking efficiently, reducing CPU strain.
What’s a normal CPU usage level?
For most systems, 5–20% when idle and 50–70% during multitasking is normal.