All arithmetical and logical functions in a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is typically called the "brains" of the PC also. The pace at which the CPU executes system instructions is typically referred to as its speed and it is measured in Hertz. The faster the processing unit is, the more quickly scripts and web apps shall be executed, even though the performance of the latter depends upon other things also - the read/write speed of the hard disk, the amount of physical memory, the network connectivity, and many others. All current CPUs have several cores, which work together. Because of this, the overall performance and the workload which a CPU can manage increase, as every single core can process a number of tasks individually and several cores can handle 1 task which cannot be processed by one core.