All arithmetical and logical functions within a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is usually called the "brains" of the personal computer as well. The pace at which the CPU completes system instructions is typically referred to as its speed and it is measured in Hertz. The quicker the processing unit is, the more quickly scripts and web applications will 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 connection, and so on. All modern CPUs have numerous cores, which work together. Therefore, the efficiency and the workload a CPU can manage increase, because every single core can process different tasks separately and several cores can handle 1 task that can't be processed by 1 core.