APC, which stands for Alternative PHP Cache, is a framework used for caching the compiled source code of a script application, that could speed up a database-driven Internet site several times. Each time a PHP webpage is accessed, the script pulls the website content which needs to be shown from a database, parses and compiles the program code, then the result is displayed to the site visitor. While this is necessary for Internet sites with routinely changing content, it's a waste of processing time and system resources for a website which doesn't change, like an informational portal which shows identical content on a regular basis. As soon as the webpages for such a website are compiled, APC caches them and delivers them any time a visitor accesses them. Since this saves the time to get content from the database and to parse and compile the code, the Internet site will load significantly quicker. APC is really effective especially for scripts with massive source code.