High CPU usage can slow down your applications, interrupt your workflows, and even cause downtime. Fortunately, you can resolve most issues quickly once you identify what’s consuming your resources. This guide walks you through the essential steps to diagnose and fix high CPU usage on both Linux and Windows servers.
Step 1: Identify What’s Causing the High CPU Usage
Start by checking which processes are consuming the most resources.
On Linux
Use top or htop to view real-time CPU activity. These tools show active processes, how much CPU they use, and how your system behaves under load.
On Windows
Open Task Manager, go to the Processes tab, and sort by CPU usage. This helps you spot any application or service that suddenly consumes more power than expected.
Look for unusual tasks, misbehaving services like Apache or MySQL, or unfamiliar processes that might indicate abuse.
Step 2: Restart Misbehaving Services
If a known service is spiking the CPU, restarting it often restores normal performance.
Linux Restart Examples
sudo systemctl restart apache2
sudo systemctl restart mysql On Windows
Open the Services app and stop or restart the affected service from there.
A quick restart reduces load while you investigate further.
Step 3: Optimize and Clean Up Your System
Next, lower unnecessary usage by reviewing what runs on your server.
- Remove outdated or unused plugins.
- Disable heavy background tasks you no longer need.
- Update your system regularly to improve stability and performance.
If you run WordPress or another database-driven application, optimize your database to reduce query load and improve CPU efficiency.
Step 4: Scan for Malware or Abuse
Unexpected CPU spikes often indicate cyber abuse, such as cryptominers, bots, or brute-force attempts. A quick security scan helps you rule out malicious activity.
Linux Malware Check
sudo apt install rkhunter
sudo rkhunter --check Also review open ports, logged-in users, or unusual network traffic. Detecting and removing threats early prevents long-term performance issues.
Step 5: Monitor and Scale If Needed
Once your server is stable again, set up ongoing monitoring. Tools like Netdata or server dashboards show CPU spikes, unusual traffic, or suspicious behavior in real time.
If your applications keep growing, consider upgrading your VPS or using load balancing. Scaling prevents constant overload and helps maintain smooth performance.
Watch Our YouTube Video on What to Do If Your Server has High CPU Usage
If you prefer a visual walk-through, watch the connected YouTube video that this tutorial is based on. It shows every step in action for both Linux and Windows.
Conclusion
Here’s a quick recap to keep your server running efficiently:
- Check what’s consuming CPU
- Restart or disable unnecessary processes
- Clean up and optimize your system
- Scan for malware or abuse
- Monitor performance and scale when needed