My website is slow or using too much CPU: here's how to speed it up

Is your website slow, or are you seeing 503 errors because your site uses too much CPU or too many processes? The cause is almost always the website itself: no caching, too many plugins, large images or a bloated database. With the tips below you'll make your site faster, and the resource usage will drop on its own.

First: where is the problem?

• Just you or everyone? Try your site on your phone over 4G or 5G, or in a private window. If it's fast there, the problem is your own computer, network or VPN.
• Are you hitting the limits of your package? In DirectAdmin, check Resource Usage. If you see faults there, your site was being throttled. See DirectAdmin Resource Usage and slow websites.
• Which page, plugin or query is taking the time? You can see that with X-Ray. Read how it works in Resource limit reached / 503 / PHP X-Ray.

Tips to make your website faster

1. Turn on caching. Our servers run LiteSpeed. For WordPress, the free LiteSpeed Cache plugin often makes your site much faster right away, because pages no longer have to be rebuilt on every visit. Also read our blog LiteSpeed Cache vs. WP Rocket.
2. Use Redis for heavy sites. For webshops and sites with lots of logged-in users, Redis helps as an object cache. Redis is included in Power Webhost Three, Power Webhost Four and Power Reseller. See Redis.
3. Shrink your images. Don't put photos of several MB straight from your camera onto your site. Resize them before uploading to the size at which you display them, or use a plugin that does it for you.
4. Limit your plugins. Every plugin costs time. As a test, disable them all and see if the site is fast. If it is, turn them back on one by one until you find the culprit. Remove anything you don't use.
5. Clean up your database. Old revisions, spam comments, statistics and log tables make your site slower over time. That's why a site that always worked fine can suddenly become slow. Clean up and optimize, see Checking, repairing and optimizing a database.
6. Use a newer PHP version. Newer versions are considerably faster. See Choosing the PHP version.
7. Check your cron jobs. A job that starts every minute and takes longer than a minute will pile up. Run heavy jobs less often and at quiet times. See Cron Jobs.
8. Keep bots and spam out. Login attempts on wp-login.php, spam through comment forms without a captcha and crawlers copying your entire site all keep your package busy. The access log shows which addresses make a lot of requests, see Site summary and logs.
9. Don't let scripts keep waiting. If your site fetches data from another server, such as an RSS feed or an integration, always give that call a short timeout. Otherwise processes stay open when that other server is slow.

What the visitor sees: speed in the browser

The tips above are about the server. How fast a page feels to a visitor also depends on what the browser has to load. Google measures this with the Core Web Vitals, which you can see in PageSpeed Insights. Four things almost always help:

• Give images a width and height (width and height). The browser then reserves space and the page doesn't jump when the photo comes in.
• Don't lazy load the most important image. The large photo at the top of a page shouldn't have loading="lazy". Lazy loading is for images further down.
• Use WebP or AVIF. At the same quality, these formats are smaller than JPG and PNG.
• Resize and compress your images to the size at which you display them.

How to read the report is explained in Reading PageSpeed Insights: Core Web Vitals in plain language. You set up caching for WordPress and a webshop with LiteSpeed Cache for WordPress and a webshop.

You'll find all the steps with explanations in My website is slow in the DirectAdmin manual.

What does the number of processes mean?

The number of processes is not the number of visitors. A web server process delivers a page and is done within a fraction of a second. If processes stay open, for example because a script is waiting on another server, your package's limit fills up. Visitors then see a 503 error or Resource Limit Is Reached. In that case, read 503 or 'Resource Limit Is Reached': what now?.

Is your package too small?

Have you cleaned up the site and turned on caching, and does Resource Usage still show faults at busy times? Then your site needs more computing power. In My WebOké, go to My Products › Manage and choose Change hosting package. An upgrade takes effect immediately after payment. Heavy sites such as webshops need more computing power than a small site, even under normal use.

Can WebOké fix it?

We can see when your site is demanding too much and are happy to give you tips. Adjusting and optimizing your website, plugins or database is something you do yourself or have your web developer do. This also applies to software you installed through Installatron: it isn't ours. See also Costs of specific work.

Want to learn more? Take the free course Getting found online, lesson 4.3 Core Web Vitals: LCP, INP and CLS.

Want to learn more? Take the free WordPress course, lesson 6.1 What makes a site slow, and how do you measure it? or lesson 6.2 Caching.