APC, or Alternative PHP Cache, is a PHP module that caches the output code of database-driven script software applications. Dynamic PHP Internet sites store their content in a database which is accessed whenever a visitor opens a page. The content that should be viewed is gathered and the code is parsed and compiled before it's delivered to the site visitor. These actions need some processing time and include reading and writing on the web server for each and every page which is opened. While this cannot be avoided for Internet sites with regularly changing content, there are various Internet sites that feature the exact same content on a number of of their pages constantly - blogs, info portals, hotel and restaurant sites, etc. APC is quite useful for this type of Internet sites as it caches the already compiled code and displays it when visitors browse the cached webpages, so the code does not need to be parsed and compiled all over again. This will not only greatly reduce the server load, but it will also boost the speed of any Internet site many times.