What is CPU? Meaning, Definition, and What CPU Stands For
What Is a CPU? Here's Everything You Need to Know
If you’re just learning about the world of computers and electronics, the terminology used to refer to different parts can be confusing. One component term you may have encountered is “CPU,” which stands for “central processing unit.”
CPUs reside in almost all devices you own, whether it’s a smartwatch, a computer, or a thermostat. They are responsible for processing and executing instructions and act as the brains of your devices. Here, we explain how CPUs interact with other parts of your devices and what makes them so integral to the computing process.
What makes a CPU a CPU?
The CPU is the core component that defines a computing device, and while it is of critical importance, the CPU can only function alongside other hardware. The silicon chip sits in a special socket located on the main circuit board (motherboard or mainboard) inside the device. It is separate from the memory, which is where information is temporarily stored. It is also separate from the graphics card or graphics chip, which renders the video and 3D graphics that are displayed on your screen.
CPUs are built by placing billions of microscopic transistors onto a single computer chip. Those transistors allow it to make the calculations it needs to run programs that are stored on your system’s memory. They’re effectively minute gates that switch on or off, thereby conveying the ones or zeros that translate into everything you do with the device, be it watching videos or writing an email.
One of the most common advancements of CPU technology is in making those transistors smaller and smaller. That’s resulted in the improvement to CPU speed over the decades, often referred to as Moore’s Law.
In the context of modern devices, a desktop or laptop has a dedicated CPU that performs many processing functions for the system. Mobile devices and some tablets instead utilize a System on Chip (SoC) which is a chip that packages the CPU alongside other components. Intel and AMD both offer CPUs with graphics chips and memory stored on them, too, meaning they can do more than just standard CPU functions.
What does a CPU actually do?
At its core, a CPU takes instructions from a program or application and performs a calculation. This process breaks down into three key stages: Fetch, decode, and execute. A CPU fetches the instruction from RAM, decodes what the instruction actually is, and then executes the instruction using relevant parts of the CPU.
The executed instruction, or calculation, can involve basic arithmetic, comparing numbers, performing a function, or moving numbers around in memory. Since everything in a computing device is represented by numbers, you can think of the CPU as a calculator that runs incredibly fast. The resulting workload might start up Windows, display a YouTube video, or calculate compound interest in a spreadsheet.
In modern systems, the CPU acts like the ringmaster at the circus by feeding data to specialized hardware as it is required. For example, the CPU needs to tell the graphics card to show an explosion because you shot a fuel drum or tell the solid-state drive to transfer an Office document to the system’s RAM for quicker access.
Cores, clocks, and costs
Originally, CPUs had a single processing core. Today’s modern CPU consists of multiple cores that allow it to perform multiple instructions at once, effectively cramming several CPUs on a single chip. Most CPUs sold today have two or four cores. Six cores are considered mainstream, while more expensive chips range from eight to a massive 64 cores.
Many processors also employ a technology called multithreading. Imagine a single physical CPU core that can perform two lines of execution (threads) at once, thereby appearing as two “logical” cores on the operating system end. These virtual cores aren’t as powerful as physical cores because they share the same resources, but overall, they can help improve the CPU’s multitasking performance when running compatible software.
Clock speed is prominently advertised when you are looking at CPUs. This is the “gigahertz” (GHz) figure that effectively denotes how many instructions a CPU can handle per second, but that’s not the whole picture regarding performance. Clock speed mostly comes into play when comparing CPUs from the same product family or generation. When all else is the same, a faster clock speed means a faster processor. However, a 3GHz processor from 2010 will deliver less work than a 2GHz processor from 2020.
So, how much should you pay for a CPU? We have several guides to give you some suggestions for the best CPUs you can buy. For a general outline, however, unless you’re a hardcore gamer or someone looking to edit videos, you don’t need to spend more than $250. You can help keep the cost down by avoiding the latest hardware and instead sticking to a recent generation of CPU.
For Intel CPUs, that means 8th-, 9th-, or 10th-generation chips. You can determine their generation by the product name. For instance, the Core i7-6820HK is an older 6th-generation chip, while the Core i5-10210U is a newer 10th-generation chip.
AMD does something similar with its Ryzen CPUs: The Ryzen 5 2500X is a 2nd-generation chip based on its new “Zen+” core design, while the Ryzen 9 3950X is a 3rd-generation CPU. Ryzen 4000 was released as a laptop chip line and in APU form with very limited availability on desktop through system builders. With that in mind, it’s arguable whether the Ryzen 5000 is the fourth or fifth generation of AMD Ryzen CPU, but it’s the latest, and most recently, AMD has unified its laptop, APU, and desktop platforms under the Ryzen 5000 banner.
How important is the CPU?
These days, your CPU isn’t as important for overall system performance as it once was, but it still plays a major role in the response and speed of your computing device. Gamers will generally find a benefit from higher clock speeds, while more serious work such as CAD and video editing will see an improvement from a higher CPU core count.
You should bear in mind that your CPU is part of a system, so you want to be sure you have enough RAM and also fast storage that can feed data to your CPU. Perhaps the largest question mark will hang over your graphics card as you generally require some balance within your PC, both in terms of performance and also cost.
Now that you understand the role of a CPU, you are in a better position to make an educated choice about your computing hardware. Use this guide to learn more about the best chips from AMD and Intel.
Editors' Recommendations
Choose A CPU
Loading Products
Sort by Most Popular Name (Ascending) Name (Descending) Price (Lowest To Highest) Price (Highest To Lowest) Rating (Lowest To Highest) Rating (Highest To Lowest) Core Count (Ascending) Core Count (Descending) Performance Core Clock (Ascending) Performance Core Clock (Descending) Performance Boost Clock (Ascending) Performance Boost Clock (Descending) TDP (Ascending) TDP (Descending) Integrated Graphics (Ascending) Integrated Graphics (Descending) SMT (Ascending) SMT (Descending)
What is CPU? Meaning, Definition, and What CPU Stands For
Every single computing device has a CPU.
You may have heard of this tech term before, but what is it exactly? What is a CPU and how does it work?
In this beginner-friendly article you'll learn the basics on what a CPU actually is, and I'l give you an overview of how it works.
What is a CPU and where do you find it in a computer?
CPU is short for Central Processing Unit. It is also known as a processor or microporcessor.
It's one of the most important pieces of hardware in any digital computing system – if not the most important.
Inside a CPU there are thousands of microscopic transistors, which are tiny switches that control the flow of electricity through the integrated circuits.
You'll find the CPU located on a computer's motherboard.
A computer's motherboard is the main circuit board inside a computer. Its job is to connect all hardware components together.
Often referred to as the brain and heart of all digital systems, a CPU is responsible for doing all the work. It performs every single action a computer does and executes programs.
What are computer programs and where are they stored?
There is a program for everything a CPU does.
You have a program that lets you use your web browser or a word processor. You have one that performs mathematical operations on a calculator or lets you type letters and characters on a keyboard. And there are programs that manage clicking and selecting elements with a computer mouse and pressing down on your laptop's touchpad.
Whatever it may be, there is a program for all computer activities.
Programs are sets of instructions that need to be executed in sequential, logical order and be followed precisely step-by-step.
They are written in a human-readable language – a programming language – by a programmer.
Computers don't understand programming languages directly, so they need to be translated to a form that is easier understood.
That form is called machine language or binary.
Binary is a base two numerical system. It's comprised of only two numbers: 0 and 1.
This reflects and ties in well with the only two possible states transistors have to control the ebb and flow of electricity – they are either on (1) or off (0).
So, under the hood, programs are stored as sequences of bits. Bits are another name for binary digits (sequences of 1s and 0s).
Programs are stored permanently and long term in a storage device, whether it's a HDD (Hard Disk Drive) or SSD (Solid State Drive).
These are non-volatile types of memory, meaning they store data even when the power is off.
While a program is up and running and currently being used, though, all of its data is stored in the main, primary, memory or RAM (Random Access Memory).
This type of memory is volatile, and all data is lost when the power shuts off.
What does a CPU do?
In a nutshell, a CPU is responsible for handling the processing of logical and mathematical operations and executing instructions that it is given.
It can execute millions of instructions per second – but can carry out only one instruction at a time.
It first receives some type of input, typically from an input device (such as a monitor display screen, a keyboard, a mouse, or a microphone) or from an application/system software program (like your web browser or operating system).
Then the CPU is in charge of four tasks:
Fetching instructions from memory, in order to know how to handle the input and know the corresponding instructions for that particular input data it received. Specifically, it looks for the address of the corresponding instruction and forwards the request to the RAM. The CPU and RAM constantly work together. This is also called reading from memory. Decoding or translating the instructions into a form the CPU can understand, which is machine lnaguage (binary). Executing and carrying out the given instructions. Storing the result of the execution back to memory for later retrieval if and when requested. This is also called writing to memory.
Finally, there is an output of some kind, such as printing something to the screen.
The process described above is called the fetch-execute cycle, and happens millions of times per second.
The main parts of a CPU
Now you know the basic tasks a CPU performs for every operation happening on a computer, what are the parts of the CPU that help get that work done?
Below are some of the important components within it:
CU (short for Control Unit). It regulates the flow of input and output. It's the part that fetces and retrieves the instructions from main memory and later decodes them.
(short for Control Unit). It regulates the flow of input and output. It's the part that fetces and retrieves the instructions from main memory and later decodes them. ALU (short for Artithmetic Logic Unit). The part where all the processing happens. Here is where all mathematic calculations take place, such as addition, subtraction, multiplication, and division, as well as all the logical operations for decision making, such as comparing data.
(short for Artithmetic Logic Unit). The part where all the processing happens. Here is where all mathematic calculations take place, such as addition, subtraction, multiplication, and division, as well as all the logical operations for decision making, such as comparing data. Registers. An extremely fast memory location. The data and instructions that are currenlty being processed during the fetch-execute cycle are stored there, for quick access by the processor.
What are CPU cores?
Earlier you learned that a CPU can typically perform just one action at a time.
It executes one instruction at a time and it does this with with the help of physical cores.
Essentially, a core is a CPU itself, a separate device inside the main CPU chip. This means that it has the ability to do just one thing at a time.
However, modern computers have the ability to support more than one core inside the main chip.
The more cores a CPU has, the greater the computational power and the more tasks that can be running and completed simultaneously, making the CPU a serial multitasker.
For example, there are dual-core CPUs, meaning there are two CPUs on the same chip and can run two instructions at the same time.
Quad-core CPUs mean there are four CPUs on the same chip, hexa-core CPUs mean there are six cores, and so on.
What is hyperthreading?
Modern CPUs also support a technology called hyperthreading.
The way this works is that a single physical core appears as multiple physical cores, making the Operating System think there are more cores than there actually are. This in turn makes the computer think it has more power than it actually has.
So, in addition to the physical cores mentioned in the section above, there are also these virtual cores, or threads as they are also called.
They aren't actual physical cores, but they appear to be so.
The combination of both physical and virtual cores make the execution time of programs even faster and give CPU even more computational power.
Conclusion
Thanks for reading and making it to the end! Hopefully you now have a better understanding of what CPUs are, what they do, and why they're so important.
If you want to know more about computer basics, have a look at this guide which goes over the basic parts of a computer.
Happy learning!