How to Fix High CPU Usage on WordPress Websites

High CPU usage is one of the most common performance problems faced by WordPress website owners. When a WordPress website consumes excessive CPU resources, it can become slow, generate 508 or 503 errors, increase server load, and even affect other websites hosted on the same server.

The good news is that high CPU usage is usually caused by a specific issue that can be identified and optimized.

In this guide, we will explain the most common causes of high CPU usage in WordPress and the steps you can take to fix them.

1. Identify What Is Consuming CPU

Before making changes, you should first determine what is actually causing the high CPU usage.

Common causes include:

• Heavy or poorly coded plugins

• Excessive WordPress cron jobs

• High website traffic

• Bots and crawlers

• Brute-force attacks

• WooCommerce background processes

• Database queries

• XML-RPC requests

• Heartbeat API requests

• Slow external API calls

• Poorly optimized themes

• Malware or compromised files

• Lack of caching

If you are using cPanel, CloudLinux, or another hosting control panel, check the resource usage section to determine whether the website is consistently reaching its CPU limit.

Do not immediately assume that WordPress itself is the problem. In many cases, a single plugin, cron job, or external request is responsible.

2. Find and Disable Heavy Plugins

Plugins are one of the most common reasons for high CPU usage.

Some plugins perform expensive database queries, generate reports, scan files, communicate with external APIs, or execute background processes.

Pay particular attention to:

• Security plugins

• Backup plugins

• Statistics plugins

• Related-post plugins

• Page builders

• WooCommerce extensions

• Broken or abandoned plugins

• Plugins that perform scheduled scans

• Plugins that continuously synchronize data with external services

How to troubleshoot

Temporarily disable unnecessary plugins and monitor CPU usage.

If CPU usage drops significantly after disabling a particular plugin, investigate that plugin further or replace it with a more lightweight alternative.

Avoid installing multiple plugins that perform the same function.

For example, running several caching, security, optimization, or database-cleaning plugins simultaneously can actually make performance worse.

3. Configure WordPress Caching

Caching is one of the most effective ways to reduce CPU usage.

Without caching, WordPress may need to execute PHP and query the database every time someone visits a page.

With proper caching, frequently requested pages can be served without executing WordPress on every request.

Depending on your server, consider using:

• LiteSpeed Cache for LiteSpeed servers

• WP Rocket

• WP Super Cache

• W3 Total Cache

• Nginx FastCGI Cache

• Server-level caching

If your server uses LiteSpeed, LiteSpeed Cache is generally a strong option because it can provide both page caching and server-level optimization.

Make sure page caching is actually working rather than simply installing the plugin.

4. Optimize the WordPress Database

A large or poorly optimized database can increase CPU usage, especially on websites with WooCommerce, membership systems, or large amounts of content.

Common sources of database bloat include:

• Post revisions

• Auto-saved drafts

• Spam comments

• Trashed posts

• Expired transients

• WooCommerce sessions

• Plugin-generated logs

• Large metadata tables

• Unused plugin data

Regularly clean unnecessary data and optimize database tables.

However, always create a backup before performing database cleanup.

For large websites, database optimization should be performed carefully rather than repeatedly running aggressive cleanup operations.

5. Reduce WordPress Heartbeat Requests

The WordPress Heartbeat API allows the browser to communicate with the WordPress server periodically.

It is useful for features such as:

• Autosaving posts

• Locking posts while someone is editing

• Real-time dashboard information

However, on some websites, excessive Heartbeat requests can create unnecessary PHP and database activity.

You can reduce the frequency of Heartbeat requests or disable them in areas where they are not required.

Be careful with completely disabling Heartbeat because some WordPress features and plugins depend on it.

A better approach is usually to control its frequency.

6. Optimize WP-Cron

WordPress uses WP-Cron to execute scheduled tasks such as:

• Publishing scheduled posts

• Sending emails

• Processing WooCommerce tasks

• Cleaning temporary data

• Running plugin jobs

• Performing automated maintenance

On a busy website, WP-Cron can become a significant source of CPU usage.

By default, WordPress may trigger WP-Cron during normal page requests.

For high-traffic websites, it is often better to disable the default WP-Cron trigger and run it using a real server cron job.

For example:

define('DISABLE_WP_CRON', true);

Then configure a system cron job to execute WordPress cron periodically.

A common setup is to run it every 5 minutes, although the correct frequency depends on the website's requirements.

This approach gives you much better control over scheduled WordPress tasks.

7. Check WooCommerce Background Processes

WooCommerce websites can consume considerably more CPU than normal WordPress websites.

WooCommerce may generate background tasks related to:

• Order processing

• Scheduled actions

• Emails

• Webhooks

• Product synchronization

• Subscription processing

• Stock updates

• Analytics

• Customer sessions

Check WooCommerce → Status → Scheduled Actions and look for large numbers of pending, failed, or repeatedly executed actions.

If thousands of scheduled actions are waiting or failing repeatedly, investigate the responsible plugin or task.

Do not simply delete scheduled actions without understanding what created them.

8. Control Bots and Crawlers

Sometimes the website is not receiving legitimate visitors—the majority of requests may come from bots.

Search engine crawlers, vulnerability scanners, aggressive bots, and malicious traffic can generate thousands of requests.

Check your:

• Access logs

• Web server logs

• Cloudflare analytics

• Security plugin logs

• cPanel statistics

Look for IP addresses or user agents generating unusually high numbers of requests.

If necessary, use:

• Cloudflare

• Web Application Firewall (WAF)

• Rate limiting

• Server firewall rules

• Bot protection

• Fail2Ban

• ModSecurity

Blocking or rate-limiting abusive traffic can dramatically reduce CPU usage.

9. Disable XML-RPC If You Do Not Need It

XML-RPC is a WordPress feature used by certain applications and integrations.

If your website does not require XML-RPC, disabling it can reduce unnecessary requests and help prevent certain types of abuse.

However, do not disable XML-RPC blindly if your website depends on:

• Jetpack

• Remote publishing

• Specific mobile applications

• Third-party integrations

Always verify whether your website actually needs it first.

10. Reduce WordPress Admin-AJAX Usage

admin-ajax.php is frequently involved in high CPU usage.

Plugins can repeatedly call this endpoint for:

• Live search

• Filtering

• Analytics

• Notifications

• Shopping carts

• Forms

• Dynamic content

• Background processes

If server logs show a large number of requests to:

/wp-admin/admin-ajax.php

identify which plugin or feature is generating those requests.

Reducing unnecessary AJAX requests can significantly improve server performance.

11. Use PHP OPcache

PHP OPcache stores compiled PHP scripts in memory so PHP does not have to compile the same files repeatedly.

Enabling OPcache can reduce PHP processing overhead and improve WordPress performance.

Make sure your server's PHP configuration has OPcache properly enabled and configured.

For high-traffic WordPress websites, OPcache should generally be considered a standard performance optimization.

12. Use a Supported PHP Version

Running an outdated PHP version can result in poor performance, security problems, and compatibility issues.

Use a modern PHP version supported by your WordPress installation, theme, and plugins.

Before upgrading PHP:

1. Create a backup.

2. Check plugin compatibility.

3. Check theme compatibility.

4. Test the website.

5. Monitor errors after upgrading.

Do not upgrade production websites blindly.

13. Optimize Images and Static Assets

Large images do not necessarily cause high CPU usage directly, but they can significantly increase bandwidth consumption and page load time.

Optimize:

• JPEG images

• PNG images

• WebP images

• AVIF images

• CSS files

• JavaScript files

• Fonts

Use lazy loading for images where appropriate.

A CDN can also reduce the amount of static content that your origin server needs to deliver.

14. Use a CDN

A CDN can serve static resources from locations closer to your visitors.

This reduces the workload on the origin server for files such as:

• Images

• CSS

• JavaScript

• Fonts

• Videos and other static assets

Cloudflare is a popular option for WordPress websites.

A CDN does not automatically fix CPU problems caused by PHP or database queries, but it can significantly reduce unnecessary origin requests.

15. Check for Malware

Unexpected CPU usage can sometimes be caused by malware.

A compromised WordPress website may be used for:

• Spam

• Cryptocurrency mining

• Malicious redirects

• Brute-force attacks

• Bot activity

• Sending unauthorized requests

• Running malicious PHP scripts

If CPU usage suddenly increases without any change in traffic, investigate the website for malware.

Review:

• Recently modified files

• Unknown PHP files

• Suspicious plugins

• Unknown WordPress users

• Server access logs

• Cron jobs

• WordPress core integrity

Security tools such as Imunify360, Wordfence, or server-level malware scanners can help identify suspicious activity.

16. Remove Unused Plugins and Themes

Simply deactivating an unnecessary plugin is not always enough.

If you no longer need a plugin or theme, remove it completely.

Unused software can:

• Increase security risks

• Add unnecessary database data

• Create background tasks

• Cause compatibility problems

• Increase maintenance overhead

Keep the WordPress installation as clean as possible.

17. Avoid Running Multiple Optimization Plugins

More optimization does not always mean better performance.

For example, running several plugins for:

• Page caching

• Database optimization

• Image optimization

• JavaScript optimization

• CSS optimization

can cause conflicts and additional processing.

Choose a properly configured optimization stack instead of installing every performance plugin you find.

18. Optimize the Theme

A poorly coded theme can generate excessive database queries and unnecessary PHP processing.

Premium does not automatically mean optimized.

If the website is using a heavy theme or page builder, check:

• Number of database queries

• JavaScript files

• CSS files

• External API calls

• Unused assets

• Dynamic widgets

• AJAX requests

For high-traffic websites, a lightweight theme can make a noticeable difference.

19. Check External API Requests

Some WordPress plugins communicate with external services.

Examples include:

• Payment gateways

• Shipping APIs

• SMS gateways

• Email services

• Currency APIs

• Social media APIs

• Product synchronization systems

If an external API is slow or unavailable, PHP processes may remain busy while waiting for responses.

Check your server logs and plugin configuration if CPU usage appears to increase whenever a particular integration is active.

20. Monitor Server-Level Resource Usage

If you manage multiple WordPress websites on the same server, the problem may not be limited to one website.

Check:

• CPU usage

• RAM usage

• PHP-FPM processes

• MySQL/MariaDB usage

• I/O usage

• Entry processes

• Concurrent connections

• Apache/LiteSpeed workers

• Load average

For CloudLinux servers, check the resource usage of individual cPanel accounts.

This helps identify which account is actually consuming the server's resources.

Recommended WordPress Optimization Checklist

For a typical WordPress website, start with the following:

Basic Optimization

• Keep WordPress updated

• Keep plugins and themes updated

• Remove unused plugins

• Remove unused themes

• Enable PHP OPcache

• Use a supported PHP version

• Enable page caching

• Optimize images

• Use a CDN

CPU Optimization

• Identify heavy plugins

• Optimize WP-Cron

• Control Heartbeat API

• Check admin-ajax.php

• Review WooCommerce Scheduled Actions

• Optimize database queries

• Block abusive bots

• Review server access logs

• Check for malware

Server Optimization

• Use LiteSpeed where appropriate

• Configure LiteSpeed Cache correctly

• Use Redis/Object Cache where beneficial

• Enable PHP OPcache

• Tune PHP-FPM

• Monitor MySQL/MariaDB

• Use Cloudflare or another CDN/WAF

• Monitor per-account resource usage

The Most Important Rule

Do not try to fix high CPU usage by simply increasing server resources.

Adding more CPU or RAM may temporarily hide the problem, but it does not necessarily fix the underlying cause.

For example, if a plugin is generating thousands of database queries every minute, upgrading from 4 CPU cores to 16 CPU cores may only delay the problem.

The correct approach is:

Measure → Identify → Optimize → Monitor

First find what is consuming CPU. Then fix the specific cause.

Final Thoughts

High CPU usage on WordPress is usually a symptom rather than the actual problem.

The most common causes are poorly optimized plugins, excessive cron jobs, database activity, aggressive bots, WooCommerce background tasks, AJAX requests, caching problems, and malware.

Instead of installing multiple optimization plugins or immediately upgrading your hosting plan, investigate the source of the CPU usage first.

With proper caching, database optimization, cron management, bot protection, lightweight plugins, and regular monitoring, most WordPress websites can achieve significantly better performance while using fewer server resources.