CPU, that's often called just "processor", is an abbreviation for Central Processing Unit. That's the core of every PC or hosting server, since it runs all of the calculations and logical input/output functions. Despite the fact that that the performance of an Internet site or an app depends on other things as well, including the amount of physical memory or the connectivity of the hosting server, the rate at which a certain processor runs determines how soon an application shall be executed. Later-generation processors have numerous cores that can severely boost their overall power and efficiency, as each and every core can take care of several processes separately or a few cores can deal with one process which needs a significant computing power. Because each and every core functions at a certain speed, this architecture can be looked at as several separate processors working together.