CPU, that's oftentimes called just "processor", is an abbreviation for Central Processing Unit. That's the core of each and every personal computer or hosting server, due to the fact that it runs all the calculations and logical input/output operations. Even though the performance of a website or an app is determined by other things too, like the amount of physical memory or the online connectivity of the web server, the speed at which a specific processor works determines how quickly an application shall be executed. Later-generation processors have numerous cores that can drastically boost their overall power and efficiency, as each and every core can handle a variety of processes individually or a number of cores can control a single process that requires a sizeable processing power. Since each core runs at a particular speed, this architecture can be viewed as numerous independent processors cooperating.