CPU, that's sometimes called just "processor", is an abbreviation for Central Processing Unit. This is the core of any PC or server, due to the fact that it carries out each of the calculations and logical input/output functions. Even though the performance of an Internet site or an application is determined by other things also, including the amount of physical memory or the connection of the web server, the rate at which a specific processor operates determines how fast an application shall be executed. Later-generation processors have a number of cores which can drastically improve their overall power and efficiency, since every single core can control several processes independently or a number of cores can take care of a single process which requires a significant processing power. As every core operates at a certain speed, this architecture can be looked at as numerous individual processors working together.