CPU, which is frequently called just "processor", is an abbreviation for Central Processing Unit. That is the core of each and every laptop or computer or server, because it carries out all the calculations and logical input/output operations. Even though the performance of an Internet site or an application relies upon other things too, including the amount of physical memory or the connectivity of the server, the pace at which a particular processor runs determines how fast a program shall be executed. Later-generation processors have a number of cores which can seriously improve their overall power and efficiency, as every core can take care of several processes independently or several cores can handle one process which needs a significant computing power. As every single core operates at a particular speed, this architecture can be seen as a few separate processors cooperating.