The 10 most important parameters of your WordPress performance

Torben Simon Meier Last updated 15.01.2021
10 Min.
WordPress  Performance: The 10 most important levers
Last updated 15.01.2021

The web is teeming with tips and tricks on how to optimize your WordPress performance. Unfortunately, the optimization measures are not always well explained and their relevance is often ignored. We show you the important starting points and tools – in a sensible order and with context. This way you can see results quickly.

So far, we've already hosted about 15,000 WordPress projects. A whole lot of data has accumulated in the process. And we're constantly being asked by customers how they can further reduce the page load time of their WordPress projects. So we've systematically analyzed the results of customers' sites over the last few years. The result: 10 measures with which you can quickly and easily optimize your WordPress performance.

One thing to keep in mind before we start. Some users see the optimization results from tools like Google PageSpeed Insights and are intimidated. Let me reassure you: you don't need to take complicated optimization measures to achieve the best loading times possible. A handful of easy-to-implement methods is all you need.

WordPress performance optimization suggestions by Google
Not all site operators would know what to do with a message like this. That's why it's important to concentrate on simple optimization steps first and tackle the more complicated measures later on.

Of course, loading time optimization isn't an end in itself. Aside from a better experience for your users, a shorter loading time also benefits your visibility on Google. I'll briefly outline what each of the optimization steps is about to give you some context.

You can work your way through this guide from top to bottom to speed up your site step by step. By the way, the first seven points also refer to the typical improvement suggestions from Google PageSpeed Insights. We discuss PageSpeed Insights in in this article in more detail.

#1 Caching: the absolute No.1 performance factor

Caching means your site doesn't have to first be requested from the webserver by the browser and then put together bit by bit. Instead, your site is loaded, i.e. completely rendered, from temporary storage.

The benefit of caching is obvious: WordPress doesn't have to build up your site new every time you open a page. As WordPress is based on PHP, which is quite slow, a cache is essential. Among other things, a cache prevents PHP from needing to be read.

In principle, there are two ways to implement a cache:

  • Caching plugins: The majority of users use a caching plugin, like W3 Total Cache , WP Super Cache. Some of these plugins are easier to set up than others. In any case, a certain amount of manual work is always necessary.
  • Via your web host: Some hosts - including RAIDBOXES - offer server-side caching. This means you're unlikely to ever need a caching plugin again. Because your hosting provider has the configuration of the cache already covered for you.

Once you've set up high-performance caching, you've already taken the most important step towards better WordPress performance. For more information, check out our article on caching basics .

#2 Tidying up WordPress

In our experience, one of the most common causes for long loading times is an overloaded WordPress installation. And because this point isn't mentioned by Google PageSpeed Insights, it takes second place in my list of improvements.

An overloaded WordPress installation usually means there are too many plugins installed. Generally speaking, the fewer the plugins, the faster the site. It goes without saying that plugins are important and you can't do without them entirely. But you should always check from time to time which plugins you really need and which ones you can delete.

Note: make sure you delete extra plugins completely and don't just deactivate them.

Improve WordPress performance: Your plugin overview shows you exactly how many plugins you have installed, activated and still have to update.
Your plugin overview shows you exactly how many plugins are currently disabled. In principle, the number of "inactive" should always be zero. If not, ask yourself whether you really need that deactivated plugin?

The same applies to deleting themes: you don't need more than one.

Why should you delete extra plugins and themes? Because they add PHP code to your site. And this also applies to disabled plugins. More PHP code makes your site overall bulkier and thus slower (and more vulnerable to attacks). As I mentioned earlier, PHP is a very slow scripting language. The less of it there is, the better.

Frequently, no longer needed plugins and themes are leftovers from function and design tests. Therefore, it makes sense to clean up your WordPress sites on a regular basis. Also, you should always try new features and designs in a test environment and not on your live site! That way you won't pile up too many leftover plugins in the first place.

#3 Images: the underestimated speed breakers

One of the most effective and simple measures to reduce page loading time is to reduce image sizes. You can save large amounts of data here. Through lossless image compression you can reduce the file size of your images without visible loss of quality. Your site barely changes in appearance but image optimization allows you to reduce its size significantly.

Estimates from the site HTTP archive show images regularly make up the largest share of the data volume of a website. Minimizing your images should therefore be one of the first steps in optimization. You can optimize images manually or use a compression plugin.

Using plugins is certainly the more convenient solution. Not only do plugins allow you to compress new pictures and their thumbnails, they also automatically optimize all existing pictures from your site. However, this service is often subject to a fee.

#4 CSS and JavaScript: sounds complicated but optimization is easy

The second-largest amount of your site data is usually JavaScript and CSS files. Many users are reluctant to make any changes here. But even without code expertise, you can easily understand what CSS and JavaScript optimization is all about. There are basically three things that can be done:

  • Summarize: CSS and JavaScript are hidden in many small single files. Normally, each of these files must be requested individually by the browser from the webserver. This creates HTTP requests that tend to increase the loading time of your site. But when scripts are combined, the number of files to be loaded, and thus the number of requests, is reduced. For example, 53 individual requests become just over a dozen. And of course, there are plugins available to do this for you.
  • Minification: CSS and JavaScript files are lines of code that enable certain functions and designs on your website. This code is written by humans. But it's read by machines. Why does that matter? Because much of what a human being needs to understand code correctly isn't needed by a computer. Spaces, comments, etc. are not needed to build your site correctly. This is exactly where plugins like Autoptimize come into play. They convert CSS and JavaScript from human to machine-readable code. This makes the individual data packets smaller and faster to transmit.
  • Compressing: After merging and reducing, the last step is to compress the data packets that are sent from the webserver to the browser. The server minimizes the file size of the individual requests and the browser unpacks and calculates them. This is faster than sending uncompressed data packets. For example, you get set up a GZIP compression with caching plugins, via manual settings in the .htaccess or your host may have already activated compression on the server.

Even without the coding expertise, it's easy to understand what the individual measures can achieve. And for each of these steps, there are plugins available to help beginners optimize CSS and JavaScript. In our article on CSS and JavaScript optimization, we cover this topic in much more detail and recommend several useful plugins.

There we go!

These were the four areas where our customers were able to save a significant amount of loading time. With relatively little effort, you can improve your WordPress performance with caching, image optimization, optimizing CSS & JavaScript, and cleaning up WordPress.

#5 Good hosting is the backbone

While the first four steps in this guide can shorten the loading time of your site, they're useless if your hosting is slowing you down. We don't just mean hardware requirements for WordPress, but rather certain technologies that show you whether a web host allows you to optimize your WordPress site in the first place.

As a rule of thumb, you should expect performant WordPress hosting to offer the following:

  • SSD hard disk
  • PHP memory limit of at least 64 MB, preferably 128 MB
  • Reliable data centers
  • Current PHP version (7.4)
  • HTTP/2 and free SSL certificate

Then there's the difference between shared hosting and separate (virtual) servers.

With shared hosting, you share the server and its computing power with other sites. Usually, this is a few dozen to a few hundred. If you have your own server, you don't have to share the computing power with anyone. Above all, it offers the advantage of performance reliability.

Although your own server doesn't automatically mean more performance, experience shows that cheap hosting plans in particular, i.e. those only costing a few euros per month, can't compete with virtual servers in terms of performance.

The finer points - less clout and more effort

Virtually every WordPress user could optimize the performance-relevant areas I've mentioned so far. Either with plugins, simple testing, or buying the appropriate products. It gets more complicated once you've optimized these areas. Because then you have to go deeper into the site structure. And individual optimization steps no longer have as much effect on your site performance.

#6 Render blocking: wrong loading order

One point that performance optimization tools like Google PageSpeed Insights repeatedly criticize is a loading order that blocks the rendering.

An example to illustrate the issue: A slider consists of images and the animation command that makes these images rotate. If the JavaScript command is loaded first and then images after, your site has a functioning slider but no images. So loading the site takes longer. You can prevent this state with the correct loading order.

While there are ways to optimize the loading sequence with plugins, our experience shows these aren't always able to fully optimize your site. Best results are usually achieved here by a web designer familiar with the functions of the website.

#7 Above the fold: optimizing the visible area of the site

Apart from the total loading time of your site, perceived loading time is an essential factor. This is the time a site visitor perceives as loading time and it can be shortened with some tricks. So a user gets the impression that the site is already completely loaded even though some parts are still loading in the background.

Especially important for the optimization of this "above-the-fold" area is optimizing the loading order. This means you prioritize content and functions that are displayed to your visitors on the first screen.

WordPress  Performance: Illustration of the "above the fold" area of raidboxes.io
The top area of raidboxes.io site visitors will see without scrolling. This is the so-called "above the fold" area. For all other information, the visitor has to interact with the site and scroll.

You can achieve this, for example, by optimizing the loading sequence. But there are also plugins that make your site loads more efficiently. And only the visible area in each case. lazy load , a3 Lazy Load are examples of such plugins. Users can therefore get all the content they need and the page load time can also benefit, especially for image-heavy sites.

#8 Cleaning up your database

Besides images and scripts, your database can also become too large. Again, there are handy tools to keep your database nice and slim. For example the plugin WP Optimization.

#9 Pingbacks and trackbacks

By default, WordPress interacts with other sites that allow pingbacks and trackbacks. Every time your site or one of your blog posts is mentioned, you will automatically be notified – and this fills your database even further.

If you don't need this feature, and the added value is negligible in my opinion, you should disable pingbacks and trackbacks. Again, with the plugin WP-Optimize. Full disclosure here: this is more of a theoretical problem. None of our customers have had any serious performance losses as a result.

#10 Prevent hotlinking

Hotlinking means that somebody links directly to an image on your server - so in the end your bandwidth is "stolen". On an Apache web server, you can prevent hotlinking by adding the following code to the .htaccess file

RewriteEngine on

RewriteCond %{HTTP_REFERER} !^$

RewriteCond %{HTTP_REFERER} !^http(s)?://(www.)?deineseite.de [NC]

RewriteCond %{HTTP_REFERER} !^http(s)?://(www.)?google.de [NC]

RewriteCond %{HTTP_REFERER} !^http(s)?://(www.)?google.com [NC]

RewriteRule .(jpg|jpeg|png|gif)$ – [NC,F,L]

To prevent hotlinking on an NGINX server, add these lines of code to your NGINX wp-config file:

location ~ .(gif|png|jpeg|jpg|svg|webp)$ {
     valid_referers none blocked server_names
	 *.example.com example.* www.example.org/galleries/ ~\.google\.;
     if ($invalid_referer) {
        return 403;
    }
}

Breakdown of the code:
location ~ .(gif|png|jpeg|jpg|svg|webp)$ {
Specifies the file extensions you want to protect from hotlinking. For example, if you still want to protect pdf files, the line of code would look like this:
location ~ .(gif|png|jpeg|jpg|svg|webp|pdf)$

{valid_referers none blocked server_names
*.deineseite.dedeineseite.de ~.google. ~.bing. ~.yahoo.;
These lines are quite long but it will help you better understand what can be done with this rule. These lines indicate which domains are allowed to hotlink your files. In this example example.com with all subdomains, as well as Google, Bing and Yahoo.

if ($invalid_referer) {
return 403;
}
If a request comes in and the requested resource is NOT on your whitelist, the server will return a 403 (Forbidden).

No access to your wp-config?

Are you wondering what you can do if your host (including RAIDBOXES) doesn't allow changes to the wp-config? In this case, there are numerous security plugins available to prevent hotlinking in the official WordPress plugin directory. One plugin that offers this function is All In One WP Security & Firewall. The plugin is active on over 800,000 WordPress sites and has an average rating of 4.8 out of 5 stars (from almost 1,000 reviews).

"And what about a CDN?"

One of the most frequently asked questions is about a Content Delivery Network (CDN). For example: "Does a CDN make my site faster for visitors in Germany?", "Why do I actually need a CDN?", "Would you recommend me to use a CDN for my blog or shop?". But in most cases the answer was: No.

To cut a long story short: a CDN makes the most sense if your users are geographically dispersed. For example, if you have customers in Central Europe, South America, and Australia. If your core target group is limited to one country, however, you can forget about using a CDN to optimize your WordPress performance.

The WordPress developer Ernesto Ruge has written a great article on the topic (in German) and I highly recommend reading it.

Conclusion: don't shy away from optimization steps that only appear complicated

WordPress users are often afraid to touch areas where, in reality, changes would be quite easy to make and would usually lead to better performance. Or they neglect these areas entirely. In contrast, things like CDNs come up again and again during consultations, even though they often don't have any effect on loading time at all.

That's why I really recommend going for the "low-hanging fruit" of optimization first. With relatively little effort, you can already make great progress in reducing your load time. Even if you're new to WordPress.

So don't be discouraged by advice and suggestions from tools like PageSpeed Insights.

At its heart, performance optimization is covered by only a few areas:

  • Reducing the size of your site
  • Reducing HTTP requests
  • Compressing the individual data packets
  • Optimizing the user experience

Once you've taken this in, you can start pulling the 10 most important levers of WordPress performance we talk about above. For more complex optimization steps, there are also experts who can bring your site performance up to scratch.

Comments on this article

Leave a comment

Your email address will not be published. Required fields are marked with * .