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What is a CPU?

The central processing unit (CPU) is a computer hardware device that acts as the brain of your computer. Find out how it works and what CPU features matter.

illustration of a Central processing unit
illustration of a Central processing unit

The central processing unit (CPU) is a computer hardware device that acts as the brain of your computer.

The central processing unit (CPU) is a small chip that connects to the motherboard. It is the main electronic circuitry that processes instructions to execute programs. Think of the CPU as your computer's central hub; all actions for your computer route through the CPU and back out to the different pieces of hardware.

In more technical terms, the CPU makes simple calculations and then performs a small number of processes based on the results of those calculations. This computer processor is what connects all the hardware and software tools to make computers function.

The central processing unit contains the following components:

  • Control unit (CU)

  • Arithmetic logic unit (ALU)

  • Address generation unit (AGU)

  • Memory management unit (MMU)

  • Cache

  • Buses

  • Clock

  • Registers

  • Wires

  • Transistors

Some modern CPUs also include graphics processing units (GPUs).

image of a CPU

How does a CPU work?

A CPU works based on a fetch-decode-execute pattern. A compiler translates computer program source code into binary digits (bits). The CPU fetches these bits, decodes the instructions, and then sends them to other pieces of hardware through pegs that connect to the CPU socket of the motherboard.

For example, when you open a program and begin typing, the CPU receives instructions from the keyboard and program on what to display on the screen. Then, it sends instructions to the graphics card to display text and images on the monitor. If you want to open or save files, the CPU coordinates with the hard drive and random access memory (RAM) to move files where you can use them.

The speed and cache size of your CPU determine how much data your computer can handle at once. Modern CPUs can have billions of transistors on a single chip, allowing the CPU to process instructions so quickly that letters seem to appear on the screen simultaneously while you type.

What is clock speed, and how does it relate to cores?

CPU clock speed is how many instructions the CPU can handle per second. It is measured in gigahertz (GHz) and is a good way to differentiate between different processor models. The clock is a wire that turns on and off, keeping all the parts of the CPU in sync. Clock speed tracks how many times that wire can turn on and off in a second, which is called a cycle. Most CPUs sit at around 3 to 5 billion cycles: a clock speed of 3.0 to 5.0 GHz.

Through the 1990s and 2000s, clock speed was one of the most important factors when choosing a processor. That began to change for modern CPUs. Processing more instructions increases heat, causing more wear and tear. So chipmakers have started focusing on other areas to improve CPU performance. This may mean that some older CPU models have a higher clock speed than newer models, though the more recent models still perform far faster.

CPU and GPU clocks

What is a CPU with multiple cores?

Also called a multicore processor, a CPU with multiple cores contains at least two processing units to enhance speed. If you feel you need more power for your business users, the number of CPU cores may make a difference. Adding more cores to a single chip increases how many instructions the computer can process at once, often improving performance.

Most laptops and desktops have two- to eight-core processors, though some desktop computer models have 10- or 12-core processors. Adding more cores to the CPU doesn’t drain the battery faster or create higher loads, but it can add efficiency and speed (and increase the price tag). This is why chipmakers have started to focus on cores as a distinguishing feature rather than clock speed.

A higher number of cores can make a considerable difference for demanding applications, like video editors, gaming, or CAD applications. Some CPUs come with as many as 64 cores. A 64-core processor is overkill for the average business user. However, companies that need high-end processors for video editing or graphic design should also upgrade their RAM (64 GB or more), graphics, and video cards to keep up.

How do you maintain a CPU?

To maintain your CPU and prevent unnecessary wear and tear, do what you can to limit overheating. CPUs perform poorly when there is not enough power or ventilation. Therefore, you should pay attention to programs running in the background, ensure good ventilation, and keep your computer clean.

A computer virus can run unobtrusively, straining your CPU. Cybersecurity best practices can help you safeguard your environment and spot potential incidents before your CPU sustains physical damage.

For peak performance, also ensure there’s good ventilation. Dust can build up on the CPU and its fan, preventing heat from dissipating. Taking the computer apart and cleaning off the dust can improve its performance.

To clean the CPU, follow these steps:

  • Power down and unplug the machine.

  • Open the computer.

  • Spray out the motherboard with compressed air.

  • Use alcohol wipes to gently remove debris.

For best results, you may need to repeat this process every few months.

Choosing a CPU for your business

The good news is that most modern CPUs are well matched for the average business user. That means you can generally choose a laptop or desktop for reasons outside the CPU, like price, hard drive, and compatibility with existing hardware. The CPU should still meet most of your goals. However, businesses with more intensive computing needs should consider the CPU more carefully.

image of hand holding a CPU

CPU brand and model

Intel and AMD are the most well-known chipmakers with the Intel Core series and the AMD Ryzen series topping the list of popular CPUs. Choosing a processor from one of these lines comes down to deciding whether you want to focus on speed or value. Historically, Intel has faster CPUs, while AMD has more efficient and affordable models. However, the newest CPU models from both brands are far closer in performance and price.

While each CPU core line has distinct potential benefits, an Intel CPU and AMD CPU should offer comparable performance for most users. Let’s look at how each model compares.

Meets basic business needs

Meets intensive computing needs

Number of cores

Clock speed

Intel Core i3



1.0–4.7 GHz

Intel Core i5



1.0–5.1 GHz

Intel Core i7




1.0–5.4 GHz

Intel Core i9




1.5–5.8 GHz

AMD Ryzen 5000



3.4–4.9 GHz

AMD Ryzen 6000



2.7–5.0 GHz

AMD Ryzen 7000




4.5–5.7 GHz

Intel and AMD offer pro versions of their chips: the Intel vPro series and the AMD Ryzen PRO series. These chip series have very similar operating capabilities but add an extra layer of security to protect against firmware cyberattacks. Businesses in highly regulated industries, like finance and healthcare, often benefit from advanced security features. However, most businesses use the standard Core and Ryzen series.

Cores and threads

To choose the right CPU for your business, determine your business needs and work backward. Basic business functions generally require four to eight cores. Many companies overestimate their processing needs, but most users don’t need anything too fancy. An i5 can generally get the job done. CPUs with 16 or more cores can support more advanced business needs, such as processing massive data files, rendering video, and navigating 3D images.

Many processors also offer multithreading options. Threading allows a single CPU to process more than one task at a time. Some processors, like the AMD Ryzen Threadripper series, have multithreading options on every core. Others, like some of the Intel Core series chips, have multithreading capabilities on half of the cores while the rest perform with a single thread.

When you compare CPUs with the same or similar cores, you might look at the multithreading capabilities to choose between the two.

Clock speeds

While clock speeds are no longer the defining characteristic for choosing CPUs, they can still play a role in the speed and power. Many CPU models include two clock speeds: the boosted max speed and the baseline speed.

Most chipmakers advertise the max speeds, but also look closely at the baseline speeds. Basic business users typically need clock speeds ranging from 2.0 to 3.5 GHz. More intensive users often require clock speeds of at least 3.0 GHz.


CPUs include a small amount of memory storage called cache. This allows the chip to access certain data rapidly when multitasking, speeding up performance. Chips with more available cache support more complex operations and programs. Basic business users usually need around 12 MB of cache on their CPUs. Advanced business users may need 20 MB or more.

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