CPU, that is often called just "processor", is an abbreviation for Central Processing Unit. That's the core of each and every personal computer or server, because it executes all the calculations and logical input/output operations. Despite the fact that that the performance of a site or an application relies upon other things also, such as the amount of physical memory or the connection of the web server, the speed at which a specific processor runs determines how quickly an app shall be executed. Later-generation processors have a number of cores which can significantly improve their overall power and efficiency, since every single core can take on a variety of processes separately or a few cores can handle 1 process which requires a substantial processing power. As each and every core operates at a specific speed, this architecture can be viewed as numerous independent processors working together.