All arithmetical and logical procedures inside a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware element is occasionally called the "brains" of the PC too. The rate at which the CPU executes system instructions is typically referred to as its speed and it's measured in Hertz. The faster the processing unit is, the speedier scripts and web applications shall be executed, although the general performance of the latter is dependent upon other things too - the read/write speed of the hard drive, the amount of physical memory, the network connectivity, etc. All current CPUs have numerous cores, which work together. Subsequently, the overall performance and the workload that a CPU can handle increase, as each and every core can process a number of tasks individually and several cores can handle 1 task that can't be processed by a single core.