APC, or Alternative PHP Cache, is a PHP module which caches the output code of database-driven script applications. Dynamic PHP websites keep their content within a database which is accessed whenever a visitor opens a page. The content that needs to be displayed is gathered and the code is parsed and compiled before it is delivered to the visitor. These actions need some processing time and require reading and writing on the server for each page that is opened. While this cannot be avoided for sites with constantly changing content material, there are a lot of sites that have the exact same content on a number of of their pages all the time - blogs, informational portals, hotel and restaurant Internet sites, etcetera. APC is very useful for this type of websites as it caches the already compiled code and shows it when visitors browse the cached pages, so the code doesn't have to be parsed and compiled all over again. This will not only minimize the server load, but it will also boost the speed of any Internet site many times.