CPU, that is often called just "processor", is an abbreviation for Central Processing Unit. This is the core of every personal computer or web server, because it carries out each of the calculations and logical input/output procedures. Although the performance of a site or an app is determined by other things too, like the amount of physical memory or the connectivity of the server, the speed at which a certain processor works determines how soon an application will be executed. Later-generation processors have numerous cores that can considerably improve their overall power and efficiency, as every core can manage numerous processes independently or a number of cores can deal with 1 process that needs a considerable computing power. Since every single core works at a particular speed, this architecture can be looked at as a number of individual processors working together.