CPU, which is frequently called just "processor", is an abbreviation for Central Processing Unit. That's the core of every PC or web server, because it performs each of the calculations and logical input/output operations. Even though the performance of an Internet site or an app relies on other things too, like the amount of physical memory or the online connectivity of the hosting server, the rate at which a specific processor runs determines how fast a program shall be executed. Later-generation processors have several cores that can seriously improve their overall power and efficiency, as each and every core can manage numerous processes independently or several cores can handle a single process which needs a sizeable processing power. As every single core operates at a certain speed, this architecture can be viewed as a number of independent processors cooperating.