APC, or Alternative PHP Cache, is a PHP module which caches the output code of database-driven script apps. Dynamic PHP websites hold their content within a database which is accessed whenever a visitor opens a webpage. The content that has to be displayed is retrieved and the code is parsed and compiled prior to it being delivered to the site visitor. These actions need some processing time and include reading and writing on the hosting server for each page that is loaded. While this can't be avoided for Internet sites with constantly changing content material, there're a lot of websites that have the exact same content on a lot of of their pages all the time - blogs, info portals, hotel and restaurant Internet sites, etcetera. APC is really useful for such Internet sites as it caches the already compiled code and shows it any time visitors browse the cached webpages, so the code doesn't need to be parsed and compiled all over again. Not only will this minimize the server load, but it'll also boost the speed of any site several times.