What Is a Central Processing Unit (CPU)?

The central processing unit, also known as a CPU, processor, microprocessor, or computer processor, is a small yet crucial piece of hardware found in any computing device, including desktops, smartphones, tablets, and TVs.

The CPU is found within a device's motherboard and contains microscopic switches that manage how electricity flows throughout its circuits. A CPU uses binary, or machine language, to decode instructions it receives from memory. From there, the CPU can execute the instructions and store that information for later use in the device's memory.

This means the CPU is regularly working with the random access memory (RAM) to store and deliver instructions for the CPU.  Read on to explore the topic of CPUs further.

Read more: Information Technology (IT) Terms: A to Z Glossary

What is a central processing unit?

A central processing unit is the main processor that has the ability to run a machine's applications and operating systems. Since the CPU is in control of the operations of a computer, it’s commonly referred to as the “brain” of the computer. A CPU typically consists of multiple components, including the following:

• Registers: Registers are a specific type of permanent memory found directly within the CPU that stores and transfers data quickly, as opposed to RAM or cache memory.

• Buses: Buses are small wires that behave as an interface to memory or a highway where data can travel between components.

• Control unit: The control unit oversees instruction processing and orchestrates data flow within the CPU and among other computer components.

• Arithmetic logic unit: The ALU performs arithmetic and logical operations on data, drawing input from CPU registers and adhering to instructions from the control unit.

• Clock: The CPU's intricate circuit requires precise synchronization, facilitated by its clock, which issues electrical pulses at regular intervals, aligning with various computer components. 

• Cache: The CPU doesn't access RAM directly; instead, contemporary CPUs rely on one or more layers of cache memory. The cache, faster than RAM and positioned closer to the processor chip, stores data, and instructions.

Devices that use CPUs

A CPU is in almost every electronic device that needs to process information to function, including all kinds of computers and smart devices. Some examples of things that use CPUs include:

• Computers

• Laptops

• Tablets

• Smartphones

• Flat-screen TVs

• Digital cameras

• Thermostats

• Smartwatches

• Computer-aided design (CAD) systems

Types of CPUs

The different types of CPUs depend on the number of cores it has, including:

• Single-core processors

• Dual-core processors 

• Quad-core processors

• Hexa-core processors

• Octa-core processors

• Deca-core processors

Cores are the processors of the CPU, and most CPUs contain at least two. Having more cores allows a CPU to complete multiple tasks simultaneously, increasing a computer's overall speed and efficiency. 

A downside of having a large number of cores is that it requires increased power consumption and has the potential of overheating. Although computers with fewer cores may lack the same speed and efficiency as multi-core devices, the lower power consumption helps to enable proper functionality. 

What is CPU clock speed?

The clock speed, or clock rate, is measured in gigahertz and describes how fast a CPU processes data within any given second. For example, a CPU with a clock speed of 4.0 GHz can process 4 billion instructions, or cycles, per second. Along with the number of cores, clock speed helps to indicate how well a CPU performs, with a higher clock speed generally implying a greater level of performance. 

However, the number of cores or clock speed alone isn’t enough to determine whether one CPU is necessarily better than another because it also depends on the type of software or applications running on the device. Similarly, as a higher number of cores has the potential to produce more heat, a higher clock speed has the same effect. That said, processors can mitigate this by lowering clock speed when it gets too warm. 

How hyperthreading enhances the pace of CPU processing

Another way to improve the performance of CPUs is through a technology called hyperthreading. Developed by Intel, hyperthreading allows an individual core to act like it has multiple cores working simultaneously, resulting in a computer that processes larger amounts of information in less time. It splits each core into two virtual cores known as threads. Hypothetically, if your computer has a dual-core CPU, hyperthreading enables you to have four virtual cores, allowing the device to handle more demanding applications and complete a greater number of processes at the same time. You can experience Intel’s Hyper-Threading Technology in the newest Intel Core™ i9 processor lineup.

Who designs and builds CPUs?

Computer hardware engineers design and develop a computer's various physical components and systems, including its memory and processors. This process involves significant testing to determine how the components work together to ensure compatibility. Hardware engineering positions exist beyond computer and phone manufacturing, such as health care, automotive, airline, and telecommunications industries.

Read more: What Is Hardware Engineering?

How to get started in computer hardware engineering

To become a computer hardware engineer, you usually need to earn a bachelor’s degree in computer engineering or a related field—such as information technology, electrical engineering, or computer science. In some cases, companies may require you to also have a master’s degree in computer hardware engineering. 

Completing an internship is a great way for you to supplement your education and gain valuable experience working with computer hardware components, as are certifications. Useful certifications for hardware engineers include CompTIA A+, Cisco Certified Technician (CCT), and Apple Certified Macintosh Technician (ACMT).

Getting started with Coursera

A CPU, a vital computer chip, is situated atop a PC's motherboard. Advancements in CPU technology have led to significant enhancements in both clock speed and capabilities. 

On Coursera, you can find a variety of highly rated courses on computers and their hardware components. Introduction to Hardware and Operating Systems from IBM is a great option if you're interested in pursuing a career in information technology or simply want to know more about operating system software and core computer components such as CPUs, motherboards, hard drives, and more.

If computer science interests you, consider enrolling in Computer Science: Programming with a Purpose offered by Princeton University. This is another excellent course in which you can develop programming skills in Java. It covers a variety of basic programming elements and provides an introduction to object-oriented programming.