All arithmetical and logical operations in a computer/server configuration are handled by its Central Processing Unit, or CPU. This hardware part is sometimes called the "brains" of the personal computer too. The rate at which the CPU executes system instructions is typically referred to as its speed which is measured in Hertz. The quicker the processing unit is, the faster scripts and web programs shall be executed, though the performance of the latter depends upon other things as well - the read/write speed of the hard disk, the amount of physical memory, the network connectivity, and so forth. All current CPUs have several cores, which work together. Therefore, the overall performance and the workload which a CPU can manage increase, because each core can process a number of tasks independently and numerous cores can handle one task that cannot be processed by 1 core.