APC, or Alternative PHP Cache, is a PHP module that caches the output code of database-driven script software apps. Dynamic PHP websites keep their content inside a database that is accessed whenever a visitor loads a webpage. The content that should be shown is retrieved and the code is parsed and compiled before it is delivered to the site visitor. These actions take some processing time and include reading and writing on the web server for every single page that is opened. While this can't be avoided for Internet sites with constantly changing content, there are various Internet sites that present the exact same content on a lot of of their pages constantly - blogs, info portals, hotel and restaurant Internet sites, etcetera. APC is exceptionally useful for this type of sites since it caches the previously compiled code and shows it any time visitors browse the cached webpages, so the code does not need to be parsed and compiled all over again. Not only will this lower the server load, but it will also raise the speed of any site several times.