WP Super Cache

The plugin helps generate static HTML files from your dynamic WordPress website. After the file is generated, the web server then serves that file rather than processing the comparatively more expensive and heavier PHP scripts as is common with WordPress. The WP Super Cache plugin will serve at least 99% of your web visitors the static cached files, and in addition it will do ‘garbage collection’  which essentially is the act of cleaning up out of date, stale cached files that have no more value after their expiry date.