APC, or Alternative PHP Cache, is a PHP module that caches the output code of database-driven script software apps. Dynamic PHP Internet sites save their content within a database which is accessed whenever a visitor loads a page. The content that should be shown is gathered and the code is parsed and compiled before it is delivered to the site visitor. All these actions take some processing time and include reading and writing on the web server for each and every page which is loaded. While this can't be avoided for websites with regularly changing content, there are many websites that present the very same content on a lot of of their webpages constantly - blogs, informational portals, hotel and restaurant websites, etcetera. APC is very useful for such Internet sites since it caches the previously compiled code and shows it each time visitors browse the cached pages, so the code doesn't have to be parsed and compiled all over again. This will not only lower the server load, but it'll also boost the speed of any website several times.