All arithmetical and logical functions inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware element is usually called the "brains" of the computer too. The rate at which the CPU runs system instructions is also referred to as its speed which is measured in Hertz. The faster the processing unit is, the more quickly scripts and web applications will be executed, although the overall performance of the latter depends upon other things also - the read/write speed of the hard disk drive, the amount of physical memory, the network connectivity, and many others. All new CPUs have numerous cores, which work together. Because of this, the effectiveness and the workload which a CPU can tackle increase, because each core can process different tasks separately and a number of cores can handle a single task which cannot be processed by a single core.