PageSpeed speeds up your Joomla! or Wordpress site and reduces page load time. This webserver module automatically applies web performance best practices to pages and associated assets like CSS, JavaScript and images.

Each optimisation is implemented as a custom filter in PageSpeed, which is executed when the server serves the website assets. Some filters simply alter the HTML content, and other filters change references to CSS, JavaScript, or images to point to more optimised versions. It generally means a quicker load which in turn means it's more likely to be rated higher by search engines.