Choosing a WordPress caching plugin

For this blog, I have been using the Comet Cache plugin for a long time. But recently I had some issues, because it used too much memory for my hosting. This resulted in some functions not working in the WordPress back-end. So, I decided to test some caching plugins.

The criteria for the plugins were:

  • provide full-page caching.
  • work without any configuration.
  • do not require changes to the .htaccess file.

The plugins I tested were:

I tested the plugins on a local installation of this blog on a PC running Manjaro Linux. I also included Comet Cache to compare performance. The test was done with Apache Bench on the frontpage and a blog post with 1000 total and 10 concurrent requests.

ab -n 1000 -c 10 http://localhost/blog/
ab -n 1000 -c 10 http://localhost/blog/some-blog-post/
requests / second (mean) Frontpage Post
WordPress 20.84 25.34
Cachify DB 35.37 31.36
Comet Cache 203.0 265.83
Hyper Cache 238.07 290.61
Simple Cache 376.19 310.67
WP Super Cache 23.58 24.94

So Simple Cache is the clear winner for running this site. It is the only plugin that is faster for the frontpage than a blog post. But I have not looked into why this is.

For Cachify I used the database as caching storage. This isn't really effective. Cachify offers to store cache in files, but this requires changes to the .htaccess file.

WP Super Cache does not seem to help. It offers support for Memcached, but that requires to install an extra service.

You should probably run you own tests, if you want to use a caching plugin. Because each site is different and uses its own set of plugins and theme. The theme for this blog uses Twig + Timber. This is not a common setup, so this might lead to different results compared to regular WordPress themes that are written in plain PHP.

[Update] Simple Cache did not reliably clear caches for this site, so I switched to Hyper Cache. The problem does not seem to happen with other sites. What causes this behaviour is unclear.