High CPU utilization may lead to a sluggish performance of a WordPress website, resource limitations, and frequent site outages. You will find that your site is loading slowly, the WordPress Dashboard is becoming unresponsive, or that your host is giving you warnings about resource overuse.
However, this doesn’t necessarily mean that your website has exceeded its hosting package limits. A poor performing plug-in, frequent database queries, an uncached request, bots, and poorly configured background processes may cause WordPress to use more CPU power than needed.
Knowing what causes the high CPU usage is key to solving the issue. One has to determine what is using the resources to determine if they need to optimize WordPress, change their settings, or upgrade their hosting.
The following is a guide on why there are high CPU usages on your WordPress server, how to determine this, and what can be done about it.
Table of Contents
Why Does the CPU Usage Spike Up on WordPress?
WordPress uses PHP to execute the application, access the database, use plug-ins and make dynamic web pages. In cases where there are more requests which have more processing to do, CPU usage is bound to rise rapidly.m
1. Inefficient Database Queries
The WordPress system uses its database to get posts, settings, user info, metadata, and plugin info. Queries that are inefficient, no indexes, bigger databases, or more than one database lookups can cause increase in processing overhead.
Example: A plugin that does some expensive queries for every single request may become resource-intensive as the number of requests increases. A big database does not necessarily mean an inefficient one; it depends on how the queries were made.
How to diagnose the problem
- Use appropriate query profiling tool in a secure environment in order to detect slow and repetitive queries.
- Prior to removing the records from the database or changing the structure of the database, examine database indexing and plugin.
2. Excessive Traffic and Bot Traffic
An abrupt surge of real users can cause overloading of the computer capacity of a website. The same effect can be caused by automated bot traffic when bots keep requesting pages, submitting forms, scanning links, or logging in.
Queries directed to “wp-login.php”, “xmlrpc.php”, and “admin-ajax.php” could possibly be checked out if they occur quite often. However, there are legitimate reasons why they would exist as well.
How to diagnose the problem
- Check whether the requests are being made repeatedly by the same parties or not.
- Rate limiting, web application firewall, or bot protection is recommended when necessary.
3. WordPress Plugins That Consume Many Resources
Plugins help expand the capabilities of WordPress but there are plugins that perform resource-heavy tasks every time a page is loaded or an action is executed by the user. Examples include search plugins, analytic plugins, security scanners, backup plugins, and page builders.
This may become a particularly big problem if the plug-in accesses the database, processes a lot of data, or carries out unnecessary processing of the request.
How to diagnose the problem
- Check newly installed and updated plugins.
- Disable each of them separately on the staging server and analyze the CPU utilization with similar amount of visitors coming.
- Simply having the plugin installed doesn’t mean it is the cause; you need to confirm the findings.
4. Too Many Uncached Requests
If a user asks for a page that is not loaded from the cache, WordPress may have to process PHP, configure it, load plugins, access the database, and create a response.
If you ask repeatedly for the same dynamically generated data, then the load may increase even further. Bad cache settings, regular purging of the cache, and pages that are not cached may cause even more trouble.
How to diagnose the problem
- Make sure your caching plugin or hosting interface has activated page caching.
- Review information about cache hits and find out which pages call PHP often.
5. Outdated PHP or Poor Server Settings
The efficiency of processing requests may be affected by outdated PHP version or poor settings of the server that WordPress is running on.
There could be an increase in CPU usage in case you share the server with some other processes. Shared hosting plans usually have resource restrictions on how much processing time your plan can use.
How to diagnose the problem
- Start by checking your PHP version and graphing the resources of your hosting account, as well as looking at error logs and process statistics.
- Request your hosting provider’s assistance to see if you are facing prolonged CPU saturation or any other limitations of the hosting account itself.
6. Theme or Custom Function Optimization
Inefficiencies with a theme or custom function may generate excessive database queries, process lots of data or perform an expensive operation on each page load.
The problem may become apparent following an upgrade of the theme, changes to the code, or customization of your website.
How to diagnose the problem
- See what changes occur in the resource usage before and after recent modifications
- Test another theme on a staging website, analyze custom code and look for redundant queries, inefficient loops, and other extra processing.
7. WordPress Cron Jobs and Background Processes
In WordPress, WP-Cron is used to manage scheduled tasks such as posting a scheduled post as well as executing some actions of plugins. The problem is that by default, WordPress performs checks during page loads, thus making additional workload for the server.
Other background processes such as backups, e-mail processing, data import, security scanning, etc., might require CPU time as well.
How to diagnose the problem
- Examine schedule, backup schedule and task queue for plugins.
- See if there is any overlap, repetitions of failure or excessively long processing time for tasks.
- Where appropriate set up a server cron to run WordPress scheduled events rather than using requests from visitors.
- Never disable WP-Cron unless you set up an alternative.
Reducing CPU Usage of WordPress
Once the probable source is determined, apply the appropriate solution instead of tinkering with many settings at once.
1. Identify the Process Using CPU
Begin with your hosting control panel. Check whether you can view any graphs or other information about your CPU usage and traffic when the problem occurs.
Associate this data with your activity on WordPress, plugin updates, scheduled events, and login logs. If you don’t have enough data available through your hosting control panel, request your host to provide you with account-specific diagnostic details.
2.Configuring Page and Object Caching
Page caching is the process whereby eligible page responses are stored in order for WordPress not to have to reproduce them for every visitor.
Database lookups could be avoided when object caching is implemented properly. Caching by the browser and CDN can also help avoid requests to the origin server for eligible static resources.
Logged-in users, shopping carts, and other such personal data should be handled properly. Caching should not make private information visible to other users.
3.Manage Background Task Execution and Bot Traffic
Schedule background resource intensive activities such as backup, import, and scan to not coincide with the peak traffic hours. Identify failed tasks that keep on retrying.
Restrict access but make sure that legitimate clients and search engines can still access your site. Do this in a way that allows your customers, search engines, and applications to function correctly.
4. Eliminate/Replace Unnecessary Plugins
Turn off unnecessary plugins and examine those that may be linked to performance issues. Replace functionality that is inefficient after testing reveals it to be a problem.
Never assume that simply deleting the database table and adding an index will solve your problem. If the issue is persistent, it may be necessary for the developer or web host to examine the code behind the scene.
5. Optimize Database Operations
Pinpoint costly queries before embarking on any database optimization tasks. Get rid of data that is not needed only when you have established that it is okay to delete.
Database table deletion or index addition should not be done blindly without knowing their purpose. In case there is any issue with querying that remains unsolved, then the problem might lie in the code itself.
6. Upgrade PHP and Analyze the Hosting Capability
The PHP that you choose to use should be compatible with the version of WordPress that you are running. In case of high CPU consumption even after the optimization of your website, consider if your plan has enough resources to cope with the workload of the site.
There are different resource allocations on shared hosting, and “understanding how shared server resources work” will be helpful.
WordPress CPU Problem Diagnosis Techniques
There are various signs of CPU issues in WordPress, based on the underlying activities taking place. What is important is to link the signs observed to the possible causes of such issues.
| Your observation | Possible Cause | Things to check |
| CPU usage is high after the installation of a plugin. | Plugin could be doing resource-intensive things. | Check the CPU usage on the staging environment with the plugin installed. |
| Request for login page comes multiple times. | Automated bots or login attempts multiple times. | Analyze access log files and use appropriate rate limiting mechanism or protection against bots. |
| Dashboard in WordPress slows down. | Expensive queries on database, ineffective plugins or background processes. | Review slow queries and analyze recent changes. |
| Resource limitation error messages displayed in cPanel. | CPU, memory, process, or any other account limits may have been exceeded. | Find out the particular limit which is being exceeded by checking the hosting resources. |
| Pages become slow during traffic peaks. | High cost queries, ineffective plugins, or background tasks | Â Find out which queries cause slowdowns, check for any recent changes, and locate resource-intensive processes. |
| CPU usage increases at intervals | Certain scheduled actions, backup, or some other background job | Examine the WP-Cron jobs, the backup schedule, and plugins actions. |
Just one of many examples: an error caused by limited resources does not necessarily mean that there is too much CPU activity. In the case of memory shortage, there should be a completely different strategy used than in the case of CPU overload or process limitations.
In case the error occurs within cPanel, this tutorial for solving the “Resource Limit Is Reached” error in cPanel will come in handy.
How to know if Your Fix Worked
You have to be sure that the solution has indeed helped lower CPU load without introducing new issues.
- You should test your website for similar loads of traffic after implementing the fix.
- You will have to compare all of the parameters with those from before. If the site outperforms the other under similar conditions, then you are more confident about the improvement.
- Whenever possible, run a test for any major change in the staging environment. Load testing can be performed in an iterative fashion to know how your website responds to traffic.
- Make notes of the changes you are making and the outcomes you are getting.
- In case the CPU usage is still high, pass on the required details, i.e., time stamps, resource graph, errors and recent website changes to your hosting provider. The details will be useful in determining whether the issue comes from WordPress, the incoming traffic, or your hosting environment.
Conclusion
High CPU utilization in WordPress is an alarm bell, but it doesn’t indicate precisely what is causing this issue. A heavy use plugin, PHP code running repeatedly, poor SQL queries, scheduled jobs, or automated traffic could be the cause of this problem.
Nevertheless, in case CPU utilization still gets to its limit when there is regular traffic on your site despite all optimizations you have made, then it becomes necessary for you to upgrade to a new hosting solution that will be able to provide the needed resources.
Looking for a Web Hosting Service for Your WordPress Website?
As you grow your website, you’ll need more resource requirements. HarmonWeb is here to assist you in considering different web hosting services that will fit your requirements. Select the right web hosting package that offers the necessary resources to your website.
