CPU, which is oftentimes called just "processor", is an abbreviation for Central Processing Unit. This is the core of every laptop or computer or hosting server, because it performs all of the calculations and logical input/output functions. Despite the fact that that the performance of an Internet site or an app relies on other things too, like the amount of physical memory or the connectivity of the hosting server, the pace at which a particular processor performs determines how fast an app will be executed. Later-generation processors have multiple cores which can severely increase their overall power and efficiency, since every single core can manage several processes separately or a few cores can take care of a single process that needs a considerable computing power. As each core operates at a specific speed, this architecture can be viewed as a few independent processors working together.