How to fix CPU problems in WordPress

Update WordPress, its Themes and Plugins.
If you’re not using the latest version of WordPress update it.
Updating your WordPress and Themes and plugins to the latest versions can often reduce high CPU usage.
If you’re running an old version take a moment to update now.
Make sure you [backup your site](Making a backup of your web site from the Plesk Panel "Backup your Site in Plesk Panel") first!

Disable WP-Cron
WP-Cron manages all the scheduled events in your WordPress site. WP-Cron is a very common cause of high CPU loads as it is called every time someone visits your website. Disabling WP-Cron and replacing with a real cron job will help reduce CPU-load.

Install a caching plugin
Caching plugins such as W3 Total Cache can help reducing CPU load by caching static copies of your pages on your web space.
If you’re already running a caching plugin, but still experience high CPU loads check your caching plugin is using the optimal settings.
See our article on W3 Total Cache recommended settings.