Choosing a WordPress Caching Plugin: Benchmarking 18 Plugin

When developing our own site, we always want to reduce the load time to a minimum, and many have done this almost as a sport, trying to gain at least 1/10 of a second. We all know how important caching is, but there are many ways to fool yourself by looking only at load time estimates. For the test, we tried to find several different caching plugins and test their performance.

A little caching remark

Google recently announced that all mobile-friendly sites (and speed is the way to be “friendly”) have a significant advantage in search results starting April 21. You may already have seen the tag “mobile friendly” in the search results. And in Google Page Insights the very first panel is adapted for mobile devices, and not for desktops. Google’s intentions are clear and loud to any SEO specialist or webmaster. Now it’s important to work on the performance of both the desktop and mobile versions of the site, which we tried to display in benchmarking.

There are several ways to improve site performance and reduce load time, but for most webmasters using a caching plugin is not only one of the easiest, but also the only way to achieve maximum results.

WordPress (and most sites on CMS) dynamically generate pages on the fly, which requires multiple database calls to retrieve various pieces of content. Caching these dynamically generated pages allows the user to see regular HTML pages. This significantly reduces boot time and offloads the server.

Test Details

The original idea was based on the use of both the simplest topic, such as 2014 , and a more complex topic, which will allow us to simulate a more “real” site. But during the tests it turned out that the effect of plugins on the speed of loading a site with the theme “2014” was minimal, and there was almost nothing to write about. But there are many tricks to improve the performance of "2014", so server tuning is more important here, rather than caching.

In order to make the tested empty site as close to reality as possible, the Novelty theme from Tesla Themes was used. The tested page of the site was designed using graphics and text, a sidebar and some plugins were added (news output, feed from Twitter / Instagram). Now we have a page that takes a relatively long time to load. Yes, this WordPress hosting was used as hosting .

Plugins that were tested:

• AIO Cache
• Alpha cache
• Bodi0's Easy Cache
• Cachify
• Flexicache
• Gator cache
• Hyper cache
• Hyper Cache Extended
• Lite cache
• Next level cache
• Really static
• Super static cache
• W3 total cache
• Wordfence falcon
• WP Fast Cache
• WP Fastest Cache
• WP Rocket
• WP Super Cache
• WP-Cache.Com
• Zen Cache (formerly Quick Cache)

There are still:

Brutal Cache - just did not work; Batcache - a plugin with a dependency on Memcache, which was not used in the current test. Auto-optimize and Widget Cache are also left out, as they are support for other plug-ins, they are not completely independent plugins.

Hosting and benchmarking tools

During the tests, we worked with the account on a shared hosting, similar to most other options. Thus, we get the download speed achievable for "budget" users. The tested site did not have traffic, search bots did not enter it during testing. The server worked with Ngnix as a proxy, and not with pure Apache.

As tools used services offered by Google, GTMetrix and Yahoo. Thanks to this, it became possible to test not only page loading speed, but also other factors, among which:

• image optimization;
• server time delay;
• minification and optimization of js and css code;
• Using browser caching
• placement of scripts;
• use of CDN, parallelization / domain sharding;
• use of gzip compression;
• number of HTTP requests.

Google PageSpeed ​​Insights

The PageSpeed ​​Insight service checks the site both from the point of view of the desktop PC and from the side of the mobile device, giving a rating on a 100-point scale. Page Speed ​​Insights is easy to use, but provides a relatively crude result that does not give a full understanding of what can be improved. Even though the tool provides insights into some of the things Google might find important, the information provided by GTMetrix and Yahoo is much more complete.

At the same time, Google does not take into account CDN during the evaluation, therefore, in some cases, the estimate is underestimated.

GTMetrix and YSlow

GTMetrix and YSlow are based on Yahoo’s Resource Productivity Guide, and are rated on a 100-point scale. These tools are much more sophisticated in terms of taking measurements. PageSpeed ​​Insight provides just a few tips on what can be improved, while GTMetrix YSlow works with at least 50 different metrics. GTMetrix also offers a waterfall chart, dissecting the loading process, as well as a highly advanced loading history. If you want to understand how to increase the productivity of your resource, this is one of the best tools.

Timing

In benchmarking, the following tools were used to determine page loading speed and test server operation under load.

Apachebench

ApacheBench is a great tool that helps you determine how many requests per second a site can withstand using various plugins. The test was performed with 1000 requests sent over 10 different threads. The test was performed 10 times with fixing the best result for each of the plugins.

It is worth noting that the use of Nginx somewhat reduces the difference between the work of the site with / without plugins. One can argue about this, but in the case of using Nginx, there is a twofold difference in comparison with Apache.

Pingdom

Pingdom is a well-known service for monitoring and testing. With each plugin, 20 tests were conducted, fixing the best result. Note that the server was located in Sweden (Stockholm), and the Pingdom server was in the Netherlands (Amsterdam).

Webwait

Webwait is a simple but very useful tool. The main task of the service is to show how long the page will fully load in your browser. Thus, this is not a server tool; the service is launched locally. Webwait loads the page again and again, and then shows the average result. In our case, the method of downloading via Ethernet, the Opera browser, was chosen. Each page loaded 101 times with average and median loading times.

So, with a description of everything, now let's proceed directly to the tests.

Google, GTMetrix and Yslow

The site pages were tested using these services, here is the result:


As you can see, some plugins simply did not appear here - the rating is the same or very close to the rating when caching is not used at all. Google gave Supercache the best rating for both desktop and mobile devices. In GTmetrix and Yslow, we see that the Fastest Cache Rocket is ahead of the rest. We tend to rate the latter as more important, since Google Page Insight uses fewer factors to measure.

So, the best plugins were WP Fastest Cache, WP Super Cache and WP Rocket Cache. Winner - WP Super Cache with work through a mobile device. Caching for mobile was also included, they did not forget about it.

Timing

As mentioned above, evaluation points are more an indicator of the quality of the site code. They give an understanding of what can be done to speed up the site, although a higher rating from the site does not mean that it loads faster than other resources. And this is a mistake - the evaluation tools give ideas for improving the site to reduce load time, but the load time is not taken into account sufficiently. You will understand this by looking at the screenshot from Pingdom.


As you can see, the tested page received 96 out of 100 points, which is probably better than 99% of the pages of any sites. However, this page takes almost 35 seconds to load. Is the result correct? Make a conclusion yourself :)

Timing is an important test, since it really measures the speed of loading pages on sites.

Apachebench

So, we test our server for its ability to support the execution of a large number of requests. The higher the number of requests per second, the better.


Without caching, the server displays a result of 18 requests per second. This is a pretty good result, which became possible thanks to the use of Nginx. Each request takes approximately 1/500 s.

Here we see that Hyper Cache Ext, WP Fastest Cache, WP-Cache.com and WP Rocket improve the result by 300% compared to working without caching. WP Rocket is the fastest and WP-Cache.com takes the second place.

The obvious advantage here is the use of caching plugins - you can hold up to three times as many requests. Using Nginx, a good caching plugin, and maybe something like Varnish, you get a server that flies.

Pingdom

Without caching, the result is about 2.8 seconds. Using almost any plug-in improves the result at least twice.

Webwait

This shows both the average and median results when testing in Webwait. The download time is slightly shorter since the Swedish Webwait server was chosen (remember, this is a browser-based, not a server-side tool).

Average load time

Median load time

As you can see, the almost unknown WP-Cache.com works quite well.

Not single caching

Of course, not everything depends on caching. An important role is played by such factors as the choice of Apache, Nginx, etc., the correct configuration, the type of server (dedicated, VPS, shared), the number of images and their optimization, HTTP requests. Actually, almost everyone knows about these factors at Habré, therefore we will not dwell on them.

Conclusion

All plugins that are presented here have different functionality. Some are very simple, while others can be compared to a Swiss knife. Super Cache, W3 and other plugins often use pros who are familiar with CDN and other tricks. Other users prefer to work with simpler plugins like Lite Cache and WP-Cache.com. By the way, WP-Cache.com, as mentioned above, is a little-known plugin that showed excellent results.

Who is the winner?

In the first place is WP-Rocket , a paid plug-in that a whole team of specialists is working on. For installation, developers ask for $ 39, and for unlimited - $ 199.

In second place is WP Super Cache . Here the results are almost the same as the leader.

In third place is WP-cache.com , an honored medalist. It seems that no less capable developers worked on the creation of this plugin than on WP-Rocket. This plugin is very easy to configure, so if you don’t want to bother with the configuration, we recommend it.