APC, or Alternative PHP Cache, is a PHP module that caches the output code of database-driven script software apps. Dynamic PHP Internet sites store their content within a database that is accessed whenever a visitor opens a page. The content that needs to be displayed is gathered and the code is parsed and compiled prior to it being delivered to the website visitor. These actions need some processing time and involve reading and writing on the server for each page which is opened. While this cannot be avoided for Internet sites with regularly changing content, there're various Internet sites which feature the very same content on many of their webpages at all times - blogs, info portals, hotel and restaurant sites, etcetera. APC is exceptionally useful for this type of Internet sites since it caches the already compiled code and shows it every time visitors browse the cached webpages, so the code doesn't have to be parsed and compiled again. This will not only reduce the server load, but it will also boost the speed of any site several times.