All arithmetical and logical procedures inside a computer/server configuration are addressed by its Central Processing Unit, or CPU. This hardware component is usually called the "brains" of the PC too. The rate at which the CPU executes system instructions is also referred to as its speed and it's measured in Hertz. The speedier the processing unit is, the quicker scripts and web programs will be executed, even though the overall performance of the latter depends upon other things as well - the read/write speed of the hard drive, the amount of physical memory, the network connection, etc. All modern CPUs have a number of cores, which work together. For that reason, the efficiency and the workload which a CPU can manage increase, because each and every core can process a number of tasks individually and numerous cores can handle a single task that cannot be processed by 1 core.