CPU, that's sometimes called just "processor", is an abbreviation for Central Processing Unit. That is the core of each personal computer or web server, since it runs 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, like the amount of physical memory or the connectivity of the hosting server, the pace at which a particular processor performs determines how fast a program shall be executed. Later-generation processors have several cores which can drastically increase their overall power and efficiency, because every single core can control numerous processes independently or a few cores can deal with 1 process that needs a considerable computing power. Due to the fact that each and every core works at a particular speed, this architecture can be seen as a number of separate processors working together.