APC, which stands for Alternative PHP Cache, is a framework used for caching the compiled source code of a script application, that could boost a database-driven Internet site several times. Any time a PHP page is opened, the script pulls the content that should be loaded from a database, parses and compiles the program code, and the result is displayed to the visitor. While this is necessary for websites with frequently changing content, it is a total waste of processing time and resources for a site that does not change, for instance an informational portal which shows the exact same content all the time. When the webpages for such a website are compiled, APC caches them and delivers them any time a visitor opens them. Since this saves the time to get content from the database and to parse and compile the code, the site will load a lot quicker. APC is very useful in particular for scripts with large source code.