Why are WordPress sites slow down?

Jan Hornung Last updated 23.01.2020
3 Min.
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You need to understand these basics in order to effectively optimize WordPress . If WordPress is slow, it can have fatal consequences for your online business: Fast sites are more popular with users and Google, generate better interaction and ultimately higher conversions and sales.

But why does WordPress sites slow down at all? So what causes a high page load time and how can the causes be combated?

What makes WordPress slow

A website written by hand is based on HTML. It is built once and is then "surfable". WordPress , on the other hand, dynamically assembles websites each time they are called up. This has many advantages, especially if your site is updated frequently, but comes at the cost of performance. This is because the site must be constantly recalculated.

Therefore, the loading time for WordPress is particularly important: Too many Plugins or a bad Theme can lead to massive drops in performance. In principle, you can counter this problem in two ways: By increasing the performance potential of your own site , i.e. by upgrading your server and choosing the right host , and by optimizing your site . In the best case, of course, these two steps go hand in hand.

Too many and too large server requests slow down WordPress

But how does the mechanism that makes WordPress slow work? The decisive factor is the communication between browser and server.

If a website is to be built, the browser sends a request to the server. The server in turn obtains the necessary information from the PHP files of WordPress . The web server translates these PHP files into browser-readable HTML code using the so-called PHP interpreter. The browser's request to the server is also called an HTTP request. In addition to the HTML code, each image, animation, etc. also generates an HTTP request. The more of these requests have to be made and the larger the data packets transferred, the longer site takes to load[1].

This means that optimization of WordPress relies broadly on two processes: Reducing the number of requests and compressing the data to be transported.

Plugins, the Theme, pictures and animations drive the inquiries upwards

So what increases the number of such "harmful" HTTP requests? Basically a missing website concept and uncompressed data. Because if you are not clear about which functionalities and which design your website really needs to function, you run the risk of overloading your site with functions and content.

Functions of your site are either part of the Themes or are integrated via Plugins . Both increase the number of HTTP requests significantly and make WordPress slow. A clear functional concept of your site and constant tidying in the backend as well as updating Plugins and Theme help to keep your site lean and thus fast.

Images and animations also produce an HTTP request every time. Therefore, it is also important to reduce their number and use them as sparingly as possible.

Many, uncompressed files make WordPress slow

Now, in addition to the number of HTTP requests, the size of the data transferred is also important. Media files take up the most space. Normally, these are images and graphics. But texts, comments and other content can also increase the size of the data packets to be transmitted.

Here, too, radical cleaning out and compression of data can help. Or you can use an intermediate storage, a so-called cache.

WordPress slow? A cache always helps!

A cache can be understood as a kind of short-term memory. For example, if a browser cache is activated, the browser can remember sites already visited for a certain period of time. It therefore remembers which contents and functionalities are displayed on the website in which form. If you have visited site once and call it up again a short time later, the browser does not have to send an HTTP request to the server, but can build up site completely "from memory".

Now caching is not a very simple topic. There are umpteen different types of caches that can be installed and activated in many different places. The fastest caching solution you usually get via Plugins like W3 Total Cache, WP Super Cache or the paid WP Rocket.

Conclusion: Reducing server requests is a good remedy for slow WordPress - but only half the battle.

The entire process of WordPress optimization is based on reducing HTTP requests and compressing the data packets to be transmitted. However, the best way to do this is to completely disable this process and activate a cache.

Therefore, the WordPress optimization can be very time-consuming. And it's only half the battle. Because without the appropriate server power and the right hostingplan you can optimize your site as much as you want: WordPress will simply remain slow. In the next two articles in this series, we will explain what you need to consider when choosing a server and host in terms of performance.


[1]: very nice and beginner-friendly introduction to the most important procedures and terms: http://www.mediaevent.de/tutorial/

RAIDBOXER from the very start and our Head of Support. He loves talking about PageSpeed and website performance at BarCamps and WordCamps. The best way to bribe him is with an espresso – or a Bavarian pretzel.

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