All arithmetical and logical procedures in a computer/server configuration are tackled by its Central Processing Unit, or CPU. This hardware component is sometimes called the "brains" of the computer system also. The rate at which the CPU carries out system instructions is also referred to as its speed and it's measured in Hertz. The quicker the processing unit is, the faster scripts and web apps shall be executed, although the performance of the latter is determined by other things too - the read/write speed of the hard disk drive, the amount of physical memory, the network connection, and many others. All current CPUs have several cores, which work together. Therefore, the effectiveness and the workload a CPU can take care of increase, since every single core can process various tasks separately and a number of cores can handle one task that can't be processed by 1 core.