CPU, that is often called just "processor", is an abbreviation for Central Processing Unit. This is the core of each PC or hosting server, as it carries out all the calculations and logical input/output functions. Even though the performance of a site or an app relies on other things too, including the amount of physical memory or the connectivity of the hosting server, the pace at which a specific processor performs determines how fast a program shall be executed. Later-generation processors have multiple cores that can significantly boost their overall power and efficiency, since each and every core can handle numerous processes independently or a few cores can control a single process which needs a sizeable computing power. Because every single core works at a certain speed, this architecture can be seen as several individual processors cooperating.