APC, or Alternative PHP Cache, is a PHP module that caches the output code of database-driven script applications. Dynamic PHP sites store their content inside a database that is accessed whenever a visitor opens a webpage. The content that should be displayed is retrieved and the code is parsed and compiled before it's delivered to the website visitor. All of these actions take some processing time and involve reading and writing on the web server for each and every page that is accessed. While this cannot be avoided for Internet sites with constantly changing content, there're various Internet sites which present the same content on many of their pages all the time - blogs, informational portals, hotel and restaurant websites, and many others. APC is quite useful for this kind of websites since it caches the already compiled code and displays it when visitors browse the cached webpages, so the code doesn't have to be parsed and compiled again. This will not only minimize the server load, but it will also increase the speed of any Internet site several times.