All arithmetical and logical procedures inside a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware component is sometimes called the "brains" of the PC as well. The rate at which the CPU executes system instructions is commonly referred to as its speed and it's measured in Hertz. The quicker the processing unit is, the faster scripts and web apps shall be executed, even though the general performance of the latter is dependent upon other things as well - the read/write speed of the hard disk drive, the amount of physical memory, the network connectivity, and so on. All modern CPUs have numerous cores, which work together. Because of this, the overall performance and the workload that a CPU can handle increase, since every core can process a number of tasks individually and numerous cores can handle one task that cannot be processed by one core.