What is a CPU or Central Processing Unit?

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What is a CPU or Central Processing Unit?

What is a CPU or Central Processing Unit?

A CPU or Central Processing unit is an integral part of all computers. But what does it do? And how does it affect your computer? If you’re wonder what a CPU is then you’ve come to the right place, this is the first in a series of articles about central processing units. I’m going to explain what a CPU is, what they do, and how you can upgrade them over the course of the next few articles. Let’s start out with the basics.

What is a CPU

What is a CPU?

If you were shopping for a computer then you might see terms like ‘i7 quad core’ or ‘i6 dual core’ and have no idea what they mean. Chances are you’re going to recognize that higher numbers usually mean a better computer, but what does it really mean? These numbers actually refer to the CPU or central processing unit inside of the computer. These units are referred to as microprocessors when there is more than one in the computer. The CPU is essentially the single most important piece of functioning hardware inside of a computer, but is useless on its own.

What does a CPU Do?

The basic function of a CPU is to perform and carry out instructions on a computer. Processors use arithmetic and input/output operations to perform all of the functions on the computer, which means that the CPU is essentially the computers brain. The CPU performs these instructions and tasks using a hardwired design called an instruction set which is mostly designed to do arithmetic, decoding, writing, and fetching. Each of these functions is carried out by an individual part of the CPU chip.

Execution of data is done by moving data files, using ALU (Arithmetic Logic Unit), and by jumping to addresses defined on the hard drive. The CPU can also write data or place it on the hard drive, can fetch data previously written, and can decode any sort of computer code used on the computer.

The Control Unit in the CPU actually controls the other parts of the processor in order to ensure that they all follow instructions. The main function of the control unit is to regulate electrical signals as instructions and tell everything else what to do. Sort of like a supervisor.

What is Bit Rate?

The most common bit rates seen in computers today are 16, 32, 64, 86, and 128. The latter two are somewhat rare while 32 and 64 are the most common. Bit rate is controlled by the integer range which directly controls the amount of memory that a computer can process at one time. So for example a standard 32 bit integer range can process roughly 4 gigabytes of information at once. However, the bit rate of the computer isn’t hugely important as many computers actually have additional units such as 128 bit floating point units to help control and create more accuracy inside of the processor. Most computers intended for general use feature both integer and floating point bit-rates so it is not always possible to determine the capabilities of the computer based solely on bit rate.

What is Clock Rate?

What is a CPU?If you’ve ever wondered what that 2.8 or 4.2 GHz number that comes on a computer means, it’s actually the clock rate of the CPU. Clock rate is the measurement of how fast the CPU can execute or perform instructions, so it is directly related to how quickly the computer works. Clock rate is measured in gigahertz which is about 1 billion per second. Therefore a 4.2 GHz processor would go through 4.2 billion clock cycles per second, or be able to execute the same number of instructions per second. While that may seem like a lot, everything on the computer including pixels on the screen are all instructions.


Parallelism refers to a technology used in a CPU to make it faster. While a processor might be able to process billions of instructions per second, it can only perform one at once without parallelism. While there are many forms of parallelism and they can be very complex, the simplest explanation is that parallelism allows the CPU to multitask rather than waiting for each instruction to finish before starting a new one.

What do Cores Do?

If you’ve ever wondered why you might want a dual core or a quad core processor instead of a single core processor, then this information is for you. Multi-core processors are essentially multiple processors plugged in together. A quad core processor is essentially four micro processing chips plugged in together. While you won’t necessarily get four times the power and speed, you do get much better handling, a lower crash rate, and the ability to handle and process more or more complex programs at once. The average internet user does not need a four or six core processor but a heavy gamer or IT tech might.

So what is a CPU? Essentially the central processing unit is responsible for executing all tasks that keep your computer running, fetch data when you need it, read and decode information, and write data and memory to the drive. All in all, it’s the control unit for your computer and now you know how it works, what it does, and a little bit about the specs.

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About The Author
Proliferate writer, sesquipedalian, techie, Apple fangirl (don't judge),tree hugger, yogi, tea drinker, zombie hunter. Into philotherianism & philomathy. Love my job. Visit me on Google +