Every WordPress site needs a caching solution to speed up the delivery of content to users. There are so many caching plugins out there and you will get lost when trying to find a good one for you. Hosting companies like SiteGround resolves this problem by providing a custom caching solution. Since we use SiteGround cloud VPS for many years, we will share our thoughts here on caching solution from SiteGround for WordPress sites.
SuperCacher and SG Optimizer
SiteGround offers server side caching of your WordPress site using two options.
- Enable caching in cPanel
- Activate plugin in WordPress site
The cPanel option is called SuperCacher and the plugin is called SG Optimizer. SiteGround uses the cPanel setup for all content management systems like WordPress, Drupal and Joomla. However, SG Optimize is a plugin dedicated only for WordPress users.
cPanel Setup for SuperCacher
- Login to your SiteGround hosting account, click on “My Accounts” tab.
- Go to cPanel and navigate to “Advanced” section to find “SuperCacher” app. Alternatively, you can use the search box to locate “SuperCacher” app.
- Click on it, to go the caching settings.
Levels of Caching
Earlier SiteGround was providing five different caching options like below. However, later they removed HHVM and Google PageSpeed modules due to compatibility issues with the servers. Below are the caching options for SiteGround users depending on the hosting plan. You can get all three levels of caching if you have shared hosting plans of GrowBig or GoGeek. Cloud VPS and dedicated server users will get all the caching level by default.
- Static caching
- Dynamic caching
HHVM Google PageSpeed Module
How to Setup Caching in SiteGround?
You can enable static, dynamic and memcached options from cPanel. But the dynamic caching needs a connection to your website. Hence, you should install and activate SG Optimizer plugin for enabling dynamic caching.
Static caching allows you to cache all static files like CSS, JS and images. You can enable for individual sites hosted in your account and flush when you want to purge the cache. It is also possible to have a wildcard to include all subdomains of a parent domain in a single line. This happens automatically when you have Let’s Encrypt SSL certificate applied with wildcard.
If you have highly changing content on your site then dynamic caching is a best fit for you. It will cache the dynamic content and store on server’s RAM to serve to the users quickly. You can enable this option in cPanel but need an additional plugin to activate this from your site’s dashboard.
Memcached is a common database level caching to speed up MySQL queries. You need to enable memcached option both in cPanel and on your site using the plugin.
HHVM and GooglePage Speed Module (Removed Now)
HHVM is the high speed option used by companies like Facebook. But this will not work effectively on SiteGround. We have faced issues with HHVM and need to disable for the site to run properly. But you can discuss with the support team and enable on your site if that works for you.
We also faced problems with Google PageSpeed module as SiteGround removed this option without informing the users. When we have other caching plugin on the site, it was having the wrong cached files. Later, after clarifications we need to purge the cache of other plugin for the site to work properly.
WordPress Dashboard Setup for SG Optimizer
Once you complete cPanel setup, login to your WordPress admin panel to complete the other caching part. Go to ‘Plugins > Add New’ and search for ‘SG Optimizer’ plugin.
Similar to any other plugin, install and activate the SG Optimizer plugin on your WordPress site. Go to the newly created menu item “SG Optimizer
> SuperCacher Config“.
SiteGround updated the SG Optimizer plugin with many other details beyond caching, now you will only see the “SG Optimizer” main menu. We will explain with the latest SG Optimizer plugin for better understanding and up to date.
SG Optimizer Plugin Options
SG Optimizer plugin has the following options.
- SuperCacher Settings
- Environment Optimization
- Frontend Optimization
- Image Optimization
This section contain options to enable dynamic and memcached settings for your site. The “Dynamic Caching” section offers the below options:
- Turn on “Dynamic Cache” option.
- Enable ‘AutoFlush Cache’, this will automatically flush the dynamic cached whenever the content changes.
- Click o “Purge Cache” button to delete all dynamic cached content manually.
Dynamic caching may create problems like breaking your website’s pages. In this case you can enter the URLs to exclude from caching or discuss with SG support to find solution for you.
Test Dynamic Caching and Enabling Memcached
After enabling dynamic caching both in the plugin as well as on the cPanel settings, click on the “Test” button under “Test URLs for Cache Status” option. You should see the status as “Cached” in green. If you see the status as “Not Cached” in red then there should be some problem. Try the following things to fix the problem:
- You can disable and enable dynamic caching in cPanel and test again.
- Delete or deactivate any other caching plugins and try.
- Deactivate and activate SG Optimizer plugin.
Enable the memcached to store the frequently accessed database queries. This will help to serve the queries faster when requested next time. Remember to enable memcached options both in cPanel and in the plugin.
We hope SiteGround will move the memcached option down below without mixing with the dynamic cache options (SiteGround updated this point to move memcached as separate option).
Note, both dynamic cache and memcached will not work with other plugins like WP Rocket and W3 Total Cache. Previously, we were using W3TC and now we use WP Rocket, so we can confirmly tell other caching plugins have compatibility issues with SG Optimizer plugin. But read on to understand why do we still use WP Rocket when SiteGround offers many caching options.
Under this section, you can enable force HTTPS and fix mixed content issue. You can also change the PHP version, enable GZIP compression and browser caching.
You can manually change the PHP version or choose the “Managed PHP” version to use the server level setup for your installation. We don’t recommend this as the version will get updated automatically when SiteGround updates on the server. However, it may cause issues with your WordPress theme or plugin.
This is a newly introduced section in the plugin after our earlier review (see the cons of SiteGround caching below). Basically you can do minification, combining CSS and JS files, defer JS for removing render blocking issue, disbale query string from static files and disable default WordPress emoji support.
This is the last option allows you to compress the images when you upload on the media library or post editor. You can also optimize all existing images and enable lazy loading of images to improve page speed score in Google PageSpeed Insights.
Testing Page Speed
The latest version of SG Optimizer plugin also including the option for testing the site with Google PageSpeed tool. You can test the desktop and mobile speed within the site using this plugin.
Features of SiteGround Caching
SiteGround claims that their caching solution is best and can improve the speed 4x. Also the site can handle 100x more visitors with dynamic caching enabled. However, the reality is different with lots of addition options available on the plugin. You can purge the cache in single click either from admin panel or from cPanel.
Cons of Using Supercacher / SG Optimizer
After testing on couple of sites, we have found basically the plugin based solution impacts the site speed in Google PageSpeed Insights. The pages load few milliseconds slower compared to the loading without plugin.
Also HHVM does not seem to work well.
Though the site can handle more visits, the plugin is not a complete solution for caching problems.
- Image lazy loading is not working when you load images from subdomains. It will break the images in this case and you should disable this option if you serve images from subdomains. We have reported this in the comments section of SiteGround, however the plugin is not supporting this for many months.
- Image compression does not seem to work properly as WP Smush shows the images are not optimized when uploading. We need to disable this option with SG Optimizer and use WP Smush to compress the images.
- As mentioned, dynamic caching will not work with W3TC and WP Rocket. You need to disable those plugins, test SG Optimizer dynamic cache to ensure it works and then enable them again.
- Similarly, memcahed will not work as the same drop-in is used by all caching plugins like W3TC and WP Rocket. W3TC will explicitly show an error message that there is an already available “memcached.php” or “advanced-cache.php” drop-in. WP Rocket will not show any error message, however it will disable the option when you have enabled it on SG Optimizer (we have confirmed this with WP Rocket team).
- No possibility to purge single page from the WordPress admin panel when you modify the content.
In summary, you need to have additional plugins for having complete caching solution for WordPress sites hosted on SiteGround. For example, W3TC is a complete solution having almost all options you need for free. But you need to be careful in enabling database / object / page caching as this will exceed server resources on SiteGround server. Alternatively, you can try the premium WP Rocket to boost your site’s speed with CSS delivery optimization.
- Easy to setup
- Site can handle more number of visits
- Free for all hosting plans except StartUp
- Integrated server solution
- Two time setup – cPanel and plugin, yet not a complete solution
- Not works on all SiteGround sites
- Not compatible with other plugins and features like lazy loading are not tested for all scenarios.