CPU, which is oftentimes called just "processor", is an abbreviation for Central Processing Unit. This is the core of every personal computer or server, because it runs each of the calculations and logical input/output operations. Although the performance of an Internet site or an app relies on other things as well, like the amount of physical memory or the connection of the server, the pace at which a given processor performs determines how soon an app shall be executed. Later-generation processors have multiple cores which can severely improve their overall power and efficiency, due to the fact that every core can manage a number of processes independently or a number of cores can take care of one process that needs a sizeable processing power. Since each core works at a specific speed, this architecture can be looked at as numerous separate processors working together.