What’s a CPU?

Understanding the Heart of your Computer

CPU stands for Central Processing Unit. In the most basic terms, a CPU (also referred to as a processor, a microprocessor or central processor) is regarded as the brain of the computer because it is responsible for handling, interpreting, processing and executing all the instructions it receives. Everything you do on your computer is based on mathematical and logic operations, and it is the CPU which controls and performs all those operations. In other words, the CPU generates output based on the input it receives.

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Right now, there are only 2 companies that make processors: Intel and AMD.

The first CPU was developed by Intel in 1971 with the help of Marcian Edward “Ted” Hoff Jr., acknowledged as one of the inventors of the microprocessor. It was called the Intel 4004; it had 2,300 transistors, performed 60,000 operations per second, and housed 640 bytes of memory. AMD came into the picture two decades later; introducing their AM386 microprocessor line in 1991.


What makes up a CPU?

CPU repair BillingsA CPU is made up of three parts: the Arithmetic and Logic Unit (ALU), the Control Unit (CU), and its Registers.

The ALU executes arithmetic and logic operations. It can perform 4 types of arithmetic operations: addition, subtraction, multiplication and division. It can do 3 types of logic comparisons: less than, equal to, and greater than.

The CU manages and directs the activities of the CPU by sending out control signals to other components of the computer. It extracts instructions from the computer’s memory, decodes the instructions, and then executes the instructions, calling on the ALU as needed.

The Registers are the CPU’s temporary memory storage centers. They store data and other information needed while a program is running, and they are meant to be accessed quickly to keep a program running seamlessly. There are two types of Registers: the instruction register contains the instructions currently being executed by the computer; the test register stores the results of the calculations being performed.

The CPU has one other important component: the clock. Not the regular clock that tells you what time it is. It’s a special clock that tells how fast your CPU can do its calculations. Generally, the higher the clock speed, the faster your CPU can execute instructions. Clock speed is measured in Hertz, where Hertz refers to the number of clock cycles per second. For example, a CPU with a clock speed of 2.8 GHz means it can perform 2.8 billion clock cycles per second, which is the equivalent of 2.8 billion instructions per second.


What are the primary functions of the CPU?

The CPU performs 4 basic steps: fetch, decode, execute and store.

The CPU starts off its operation by fetching or retrieving the instructions it needs to run from the program memory. Each instruction is stored at a specific address, and the CPU knows which address it needs to access to retrieve the instructions.

Next, the CPU decodes the instructions by breaking it down from the original language it is written to what is known as the Assembly Language, which is the language the CPU knows and understands. In short, the instructions are translated into binary code so the CPU can understand and manipulate it.

After decoding comes execution. This means doing one of three things: perform calculations using its ALU; move data from one location to another; or jump to a different address.

Finally, the CPU should produce some kind of output and write it into the computer’s memory.

This entire process is repeated over and over until the task is completed or the program is done.

Which CPU is best for me?

The best answer is: it depends on what you need a computer for, and how much you’re willing to spend for it.

Typically, you base your considerations on the speed of the chip and the number of cores it has. The higher the speed of the chip and the higher the number of cores, the more data it can process and the faster it can do the processing.

If you’re into games and tasks that are data and graphic-intensive, and you have enough budget for it, go for Intel. AMD is a cheaper option, but it’s not exactly in the same league as Intel.


iDoctor Fixes Computers

We offer IT services to those living in Billings. If your computer is acting up, has a virus, or is downright broken, bring it in! We have computer repair specialists that can help solve your issues, and get your technology working for you again.

Questions on what we can do? Call us at 406-534-2547 to get the West End store, or call us at 406-206-3437 to reach the store in the Heights.