WordPress 5.0 vs. 4.9 – The Performance Test

Jan Hornung Last updated 21.10.2020
8 Min.
WordPress  5.0 and Gutenberg_Performance comparison
Last updated 21.10.2020

The update to WordPress 5.0 is just around the corner. However, the exact release date depends on when the new WordPress editor alias "Gutenberg" is ready for the WP core. Many WP users are worried about problems with Plugins, Themes and the performance of their site after the update. For this reason, we have taken a closer look at the update and measured whether WordPress 5.0 actually leads to the feared load time losses.

Update: The article refers to a test we did in the alpha phase of Gutenberg-Plugins . On December 6, 2018, WordPress 5.0 came out with the Gutenberg-editor. In our e-book you will learn what the new editor means for your business and how to prepare your website for Gutenberg . To find out if Gutenberg can keep up with established page builders in the meantime, check out this article from Tariq Baig.

Gutenberg and WordPress  5.0 E-Book

The upcoming WordPress update to version 5.0 has one main actor: the so-called Gutenberg editor. After the integration into WP-Core, however, this project name will be history in order not to confuse new WordPress users unnecessarily. At least that's the plan. But first, let's get to the most important question: What exactly is the Gutenberg editor anyway?

Gutenberg should revolutionize WordPress

If you are already familiar with the basics ofGutenberg, then jump directly to our WordPress 4.9 vs. WordPress 5.0 performance comparison.

With the big update to WordPress 5.0, Gutenberg will soon replace the classic TinyMCE editor, with which WP users have been able to create posts and sites without great HTML knowledge for over 10 years. However, those who want to create more complex layouts will quickly reach their limits with the TinyMCE editor without HTML knowledge and shortcodes.

This hurdle should be removed by Gutenberg to make WordPress even more accessible and user-friendly. The basic principle behind the new editor is a series of blocks that provide specific functions. For example, there are blocks for headlines, text, columns, quotes, lists, images, videos, widgets, and so on.

WordPress 5.0 brings more JavaScript and uses the WordPress REST API

The new editor brings with it another change: JavaScript. "Most WordPress developers are pretty comfortable with PHP and front-end development, though Gutenberg blocks are heavily JavaScript based," writes WP developer Rich Tabor in his Beginner's Guide to Building Gutenberg Blocks. It's not for nothing that WordPress co-founder Matt Mullenweg already told the WP community in the State of the Word 2015 he gave the WP community the homework assignment "Learn JavaScript deeply!

Because of these fundamental changes in WordPress 5.0, we are curious to see how Gutenberg's use of JavaScript and the WordPress REST API on the performance of various WordPress sites . This is because it shifts a lot of processing power from the web server to the client, which should result in a shorter load time under load. But we'll get to that in a moment.

WordPress 5.0 is a step towards Pagebuilder

Within the WP community, it is often said that WordPress offers users "What you see is what you get" (WYSIWYG). However, the reality is often different. Anyone who works with WordPress knows that you don't always get on your site what you saw in the backend.

Gutenberg should close this gap and bring WordPress a big step closer to WYSIWYG. To this topic and the new possibilities by the Gutenberg-Editor I can you the presentation by Morten Rand-Hendriksen and Mullenwegs State of the Word 2017 from WordCamp US.

The fact is that Gutenberg will initially only be introduced at the editor level, but that is only the beginning. Mullenweg's vision is to make the whole of WordPress block-based in order to keep up with the competition from website construction kits such as Wix, Medium and Co.

The next step - so what comes after what you just saw, when we finished the editing experience, is the Gutenberg-based site customization. - Matt Mullenweg, State of the Word 2017

So for the future this could provide a paradigm shift in WordPress , away from the familiar structure of Plugins and Themes and towards a single giant page builder.

WordPress 5.0 causes concerns due to the "Gutenberg- compulsion".

The fact that Gutenberg becomes the standard editor with WordPress 5.0, i.e. is virtually forced upon WordPress users, is not welcomed by everyone. For example, Plugin and Theme manufacturers must check their products for Gutenberg compatibility, adapt them if necessary or completely rethink them.

Also for operators of WordPress sites are increasingly asking questions: What impact will this have on my business? Will WordPress 5.0 slow down my site ? Will my Plugins still work? Will the update do me any good if I don't use the editor at all?

For this reason, today we detach ourselves from the discussion about Gutenberg, blocks and co and devote ourselves to the following questions:

1. is there a performance difference between WordPress 5.0 and 4.9?

2. should you even update to WordPress 5.0 given the current uncertainties?

Load time comparison: WordPress 4.9 versus WordPress 5.0

For our systematic comparison of the two WordPress versions, we looked at two key performance indicators: the page load time for a single call and the behavior of sites under load.

For the load time comparison, we prepared four sample pages whose load times we systematically compared under WP 4.9.4 and WP 5.0 (in 5.0-alpha-42852). For this we have used the tool Webpagetest tool for this purpose.

And to say it in advance, there are no serious differences.

Test 1: WordPress 5.0 tends to slow down an empty WP site

In the first test, we compared the loading times of a completely empty WP site under WordPress 5.0 and 4.9. The result: The Time To First Byte (TTFB) and the perceived loading time of site (Load Time) have slightly increased with WordPress 5.0. The total load time has slightly decreased. However, this difference is completely compensated for when looking at the cached results at the latest.

The conclusion of this first test: The differences in the measured values are probably fluctuations in the measurement itself and not systematic loading time differences.

Test 1: Empty WP site   Loading time
On both tested DEMO BOXES the Theme Twenty Seventeen is active and the Themes Twenty Sixteen and Twenty Fifteen are installed. There are no Plugins on the site . On both sites the RAIDBOXES cache is active.

Test 2: How does an online shop behave under WordPress 5.0?

In the second step, we used the same test setup for a sample shop. Here, the start page of the shop was called up in each case. In addition to WooCommerce , more than 50 other Plugins were installed on the test page, more than 45 of which were active during the test.

The shop equipped with products and functioning payment gateways also shows no major differences in the test with regard to important performance indicators.

The TTFB, load time and webpagetest speed index only vary slightly. Here, too, the differences become even smaller with cached calls.

est 2: Example shop at WordPress  5.0
Especially in the cached state you can clearly see that the differences between the two WordPress versions are vanishingly small.

Conclusion for shop owners: With a realistic and quite extensive shop we could not find any systematic differences between WP 4.9.4 and WP 5.0 - a good sign!

Test 3: How does a blog behave under WordPress 5.0?

Even in our test with a typical blog - with extensive social media connection and more than 20 Plugins, such as Yoast SEO, WP Smush, Akismet and Contact Form 7, there are no really big differences in the important load time metrics: server response time, perceived load time and total load time differ only slightly between the WordPress versions.

Conclusion: Looking at the Speed Index and the Start Render Event, the blog seems to load a little bit faster under WP 4.9.4, but all in all there are probably no significant differences.

Test 3: Example blog WordPress  5.0
In the blog load time test, the differences seem to be slightly larger, but really impressive differences do not show up.

Test 4: What about a corporate site at WordPress 5.0?

On the company page we tested, interesting differences become apparent for the first time: Although TTFB, the Start Render Event and the Speed Index are quite close to each other, there is a big difference of 1.8 seconds in the perceived total loading time.

However, this value can be explained by a faulty resource. If this is removed, the load time values equalize again. The conclusion is also here: On the company website we tested with custom Theme and 9 Plugins (including WPML, Advanced Custom Fields and a tool for landing pages), there are no relevant differences between WordPress 4.9.4 and WordPress 5.0.

Test 4: Example company website WordPress  5.0
The difference in load time leveled out after we removed the faulty resource. Thus, the above test is a perfect example of how susceptible load time measurements are to even the smallest errors, such as a faulty image.

Interim conclusion: WordPress 5.0 is not a performance guzzler

Our first analyses with an alpha version of WordPress 5.0 show that the new WP version will probably not be a performance glutton - at least not in the frontend. No matter if with or Gutenberg: According to our measurements, there are no relevant differences. From a performance point of view, nothing speaks against an update to WordPress 5.0.

Quite the opposite: Looking at the results of our load test, the update could be well worth it.

Important: Of course, these results may still change over time. Also Plugins and Themes and their compatibility with the new WP version will play a decisive role here.

Test 4: WordPress 5.0 shows better load handling

In addition to the loading time of a site , it is also important how many simultaneous accesses the site can handle before it times out. And here you can see serious differences between WP 4.9.4 and the version of WordPress 5.0 we tested.

For our test we have created an empty WP site with the tool Loader.io with 500, 750 and 1.000 uncached requests per minute and the result is remarkable. While the site with WP 4.9.4 already goes down at 750 requests per minute and shows an average response time (i.e. Time To First Byte) of 4.9 seconds, the site with WordPress 5.0 is much more stress resistant.

Even with 1,000 requests, the average TTFB of site is still - not good but stable - 863 milliseconds. This is less than one ninth of the value of site with WordPress 4.9.4.

Test 5: Load test empty WP site

We honestly found this difference hard to believe, but even on the third, fourth and fifth runs, the differences remained stable.

This result surprised us so much that we also performed the same test with the Apache benchmark tool in the backend. Here, too, the result is astonishing: The site under WordPress 5.0 can process 50 percent more requests than the site under WordPress 4.9.4.

Due to the optimization of the source code in WordPress 5.0, some resources are saved on the server side. This means that the available resources can handle more requests at once.

Conclusion: WordPress 5.0 has positively surprised us.

The final extent to which WordPress 5.0 will change the performance of your site will only become apparent in the beta and full version. However, one thing is certain: WordPress 5.0 runs much more stable under load than version 4.9.4 in our test.

From a load compatibility perspective, we can only recommend the update to WordPress 5.0 at this time. However, as mentioned above, many things can still change before the release, including these test results. 

On top of that, we focused completely on performance in these tests. Once the WordPress 5.0 beta is released, we'll also be looking at compatibility with Plugins and Themes and the general functionality of the Gutenberg editor. Only then can we make a definite update recommendation. So we'll keep an eye on this topic and hopefully we'll be able to provide you with fresh data soon.

Have you tested WordPress 5.0 or the Gutenberg-Plugin yet? Then leave me a comment, I'm happy about more experiences!

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.

Comments on this article

Post a comment

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