A central processing unit (CPU) is the part of a computer that is in charge of interpreting and executing programs and coordinating the work of all other components.
A central processing unit, also known as a processor or CPU, acts as the “brains” of the computer — it is the component that performs the arithmetic, logic and control operations specified in any program. The concept of a CPU has been in use in computer science since as early as the 1950s.
Most modern CPUs are microchips containing millions of microscopic transistors. Each of those transistors can turn on and off, representing the ones and zeroes of the binary system. By working in combination, these transistors allow even smartphone CPUs to perform billions of calculations per second.
In addition to performing its own operations, a CPU also directs the work of other components of a computer: the random-access memory (RAM), the graphical processing unit (GPU) and others.
One of the primary characteristics defining the computational power of a CPU is its clock speed, usually measured in gigahertz (GHz), which very roughly corresponds to the number of calculations a CPU can perform per second.
The ability of CPUs to perform large numbers of computations every second has resulted in their use for cryptocurrency mining — which relies on the calculation of millions of hash functions in order to find a random output whose value will be below a given target — in the early years of the crypto industry.
However, as the industry grew and the competition between miners became more fierce, the computational power of CPUs became insufficient. Ultimately, they got displaced in favor of more economically feasible tools, such as GPUs and the highly specialized application-specific integrated circuits (ASICs).