CPU, that's frequently called just "processor", is an abbreviation for Central Processing Unit. This is the core of every PC or hosting server, since it executes each of the calculations and logical input/output functions. Although the performance of a website or an application relies on other things also, such as the amount of physical memory or the connectivity of the server, the pace at which a particular processor runs determines how fast an application shall be executed. Later-generation processors have several cores that can seriously improve their overall power and efficiency, as every core can take on numerous processes separately or a few cores can deal with one process that requires a substantial computing power. Since every core functions at a specific speed, this architecture can be seen as several independent processors cooperating.