APC, which is an acronym for Alternative PHP Cache, is a framework used for caching the compiled source code of a script app, which could speed up a database-driven website several times. Each time a PHP webpage is opened, the script pulls the content that needs to be loaded from a database, parses and compiles the code, and then the result is displayed to the website visitor. While this is necessary for sites with routinely changing content, it is a complete waste of processing time and system resources for an Internet site that does not change, for instance an informational portal which displays the same content all the time. Once the webpages for such a site are compiled, APC caches them and delivers them whenever a user loads them. Since this saves the time to get content from the database and to parse and compile the program code, your website will load much quicker. APC is very efficient especially for scripts with massive source code.