CPU, which is oftentimes called just "processor", is an abbreviation for Central Processing Unit. That's the core of any personal computer or hosting server, due to the fact that it runs each of the calculations and logical input/output operations. Though the performance of an Internet site or an application depends on other things too, such as the amount of physical memory or the connection of the web server, the pace at which a particular processor operates determines how quick a program shall be executed. Later-generation processors have several cores which can severely increase their overall power and efficiency, because each core can manage a number of processes independently or several cores can take on one process which requires a considerable computing power. Because each core runs at a certain speed, this architecture can be seen as several independent processors cooperating.