CPU, that's oftentimes called just "processor", is an abbreviation for Central Processing Unit. That is the core of each and every PC or hosting server, since it runs all the calculations and logical input/output functions. Though the performance of a site or an app relies upon other things also, such as the amount of physical memory or the connectivity of the server, the speed at which a particular processor works determines how quick a program shall be executed. Later-generation processors have a number of cores that can drastically boost their overall power and efficiency, since every core can take care of several processes individually or a few cores can control a single process that requires a substantial processing power. Due to the fact that every core runs at a specific speed, this architecture can be seen as several individual processors cooperating.