Something a little different today. We are going to take a look at how much of an improvement caching plugins can make to the performance of your WordPress website. In this post I will be showing tests completed on the 4 most popular WordPress caching plugins.
These are not in-depth tests. Instead they are simple install and activate tests designed to see what speed increase you would get if you were an average user who might download, install, and enable the plugin without going into and adjusting the finer settings. In my opinion this is one of the most important tests as from my own experience a lot of users will install the plugin and hope it will work without adjustments to the configuration.
Tests were completed on a fresh WordPress install in a Docker container running PHP 7 (with OpCache), Apache and MariaDB. Demo content was installed to give the database some content and the theme Gadgetry was used. The theme was used because it is relatively heavy in content, and somewhat old. This will give a heavy default page load giving the caching plugin the best possible chance of improving loading time.
All times recorded are the time taken to load only the HTML itself and were taken from the Network tab of Firefox’s Developer tools. It does not include scripts, images, or any other requests. Also due to it being a local Docker container there should be no DNS or network request delay.
1. Comet Cache (Free)
First up is the free edition of Comet Cache. Comet Cache is one I have used previously on client websites and I find it functional, and in most cases an enable and forget cache. It has advanced features for those that need them (even in the free version), and has never failed (yet) to give me functionality straight out of the box. Now let’s get to speeds.
- Without Cache: 643ms
- With Cache: 85ms (86.78% Speed Increase)
A pretty good result. A nice 86% increase in speed and the ‘Without Cache’ load time is not too bad. I’ve noticed adjusting certain settings can increase the speed a little more but as I mentioned this is all about out of the box speed.
2. W3 Total Cache (Free)
One of the more complicated caching plugins to use effectively and sometimes not a very good contender for the ‘out of the box’ requirement. In this case I had to manually add
.htaccess rules to my install, however there were fairly good instructions included. It is still quite unfriendly for those who have very little or no technical experience though.
- Without Cache: 1.677s
- With Cache: 41ms (97.55% Speed Increase)
No, that isn’t a mistake. With the plugin installed and no cache file created it takes a whopping 1.6s. I did the test for ‘Without Cache’ numerous times to be sure and all requests hit around about the same time (± 100ms). This means that while there is a very impressive 97% speed increase, any request that causes the cache to be renewed will take a while to load.
3. WP Fastest Cache
A relatively new cache to me, I have only used this cache a few times. Fairly simple to use and good ‘out of the box-ness’, just tick the checkbox and you are ready to go. There are some nice settings in there if you need advanced features, but a few of the good ones are locked behind a premium wall (image optimisation and DB).
- Without Cache: 574ms
- With Cache: 66ms (88.5% Speed Increase)
A good speed increase again with 88% and the load time with no cache available is nice and low too. In fact the lowest so far.
4. WP Super Cache
The classic plugin for WordPress caching. Pretty much everyone in the WordPress community has heard of WP Super Cache at some point or another. Easy to install (in most cases) on Apache, nginx can get tricky. The only caveat I have found is to go into the ‘Advanced’ settings and make sure you select PHP or Mod_Rewrite caching to get the best performance.
- Without Cache: 474ms
- With Cache: 36ms (92.4% Speed Increase)
Another good result when it comes to the percentage of speed increase, but also really good when it comes to the un-cached load times.
You’ve probably already guessed what is coming. If we are talking objectively and from the testing I performed, I would have to say WP Super Cache is still the king/queen of the WordPress caching plugins, under the caveat you are using Apache. Comet Cache and WP Fastest Cache are both very good alternatives. W3 Total Cache is probably best for you if you require the most compatibility with other caching solutions like Varnish, Memcached etc.
Disclaimer: I am not associated with any of the creators of the plugins tested here. I have not been paid or given any incentives to promote or test any of these plugins. This was all undertaken in the interest of information and while I have tried to make sure all information is as accurate as possible, your mileage may vary.