APC, which is an acronym for Alternative PHP Cache, is a framework used for caching the compiled source code of a script application, that can speed up a database-driven website several times. When a PHP page is accessed, the script pulls the content that has to be shown from a database, parses and compiles the program code, and then the result is displayed to the site visitor. While this is necessary for Internet sites with constantly changing content, it's a waste of processing time and system resources for an Internet site which does not change, for example an informational portal that displays identical content at all times. As soon as the pages for such a site are compiled, APC caches them and delivers them each time a visitor opens them. As this saves the time to collect content from the database and to parse and compile the code, the website will load considerably quicker. APC is very efficient especially for scripts with massive source code.