All arithmetical and logical functions within a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware element is typically called the "brains" of the PC too. The pace at which the CPU carries out system instructions is generally referred to as its speed and it's measured in Hertz. The faster the processing unit is, the quicker scripts and web applications shall be executed, although the overall performance of the latter depends on other things too - the read/write speed of the hard drive, the amount of physical memory, the network connection, and so forth. All newer CPUs have a number of cores, which work together. Subsequently, the efficiency and the workload which a CPU can tackle increase, as every single core can process a number of tasks separately and several cores can handle one task which cannot be processed by one core.