All arithmetical and logical functions inside a computer/server configuration are tackled by its Central Processing Unit, or CPU. This hardware element is occasionally called the "brains" of the personal computer too. The rate at which the CPU completes system instructions is commonly referred to as its speed and it is measured in Hertz. The faster the processing unit is, the faster scripts and web apps shall be executed, though the 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 connection, and many others. All current CPUs have a number of cores, which work together. For that reason, the functionality and the workload that a CPU can manage increase, due to the fact that each core can process different tasks individually and numerous cores can handle a single task that can't be processed by one core.