CPU, that's oftentimes called just "processor", is an abbreviation for Central Processing Unit. This is the core of each and every laptop or computer or web server, as it runs each of the calculations and logical input/output operations. Though the performance of an Internet site or an app relies on other things too, including the amount of physical memory or the connection of the web server, the rate at which a given processor works determines how fast an application shall be executed. Later-generation processors have multiple cores that can considerably boost their overall power and efficiency, because each core can manage several processes individually or several cores can take care of a single process which requires a sizeable processing power. As every core functions at a certain speed, this architecture can be seen as several individual processors cooperating.