What Is a CPU? How to Compare Processors Simply
The central processing unit (CPU) is the part of the computer that runs instructions. Every click, keystroke and calculation passes through it. When people talk about a fast computer, they often mean a fast CPU, but the numbers printed on the box can be confusing. This guide explains what matters.
Cores and threads
A core is a separate worker inside the processor. A 4-core chip can run four tasks at the same time. Threads are virtual workers that some cores can run in parallel, and manufacturers often advertise them as "logical processors". More cores help when you run many programs or use software that splits work across cores, such as video rendering.
Clock speed
Clock speed, measured in gigahertz (GHz), counts how many cycles per second the processor completes. A higher number usually means faster work, but it is not the whole story. Two chips with the same clock speed can perform very differently depending on their design, so compare chips in the same family or use independent benchmark results.
Generations and families
Each new generation usually improves speed and power efficiency. A newer mid-range chip is often faster than an older high-end one. Check the model name and release year, not only the number of cores.
| Your use | What to prioritise |
|---|---|
| Office and web | A recent 4-core or 6-core chip, good efficiency |
| Gaming | Strong single-core speed and a suitable graphics card |
| Video editing and rendering | More cores and threads |
| Laptops on battery | Power-efficient design and good battery life |
Cooling and heat
A processor slows itself down when it gets too hot, a behaviour called thermal throttling. This is why a laptop with a good cooling system can outperform a thin one with the same chip. Keep vents clear and the computer on a hard surface to help it stay cool.
Integrated graphics
Many processors include a graphics unit on the same chip. This is enough for office work, video streaming and light photo editing. You need a separate graphics card for demanding games or 3D work.
How to check your current processor
- Windows: right-click Start, choose System, then About. The processor name is listed under Device specifications.
- Mac: choose the Apple menu, then About This Mac.
Frequently asked questions
Is a higher GHz always better?
No. Compare the model, generation and benchmark results. A newer chip at a lower clock speed can be faster.
Can I upgrade the processor?
Sometimes, on a desktop with a compatible socket. Laptop processors are usually fixed to the board. Upgrading the processor often means checking the motherboard compatibility first.
See also what a graphics card does.
Benchmarks you can trust
Independent reviewers publish test results for processors on common tasks such as video encoding, gaming and office work. Compare those results for the tasks you care about rather than relying on the number of cores alone. A benchmark from the same test suite is the best way to compare two chips side by side, because the conditions are the same.
Balance with the rest of the system
A powerful processor paired with slow memory or a hard disk will still feel slow in daily use. The processor is one part of a system, so spend your budget on balanced parts. A mid-range chip with fast storage and enough memory often feels better than a top chip with too little of the other parts.
Related reading
- What Is a GPU? Do You Need a Graphics Card?: What a graphics processing unit does, when integrated graphics are enough, and how to choose a graphics card for games and creative work.
- Mac Basics for Windows Users Switching Over: The main differences between macOS and Windows, and the Mac habits that make the switch easier: Finder, Command key, Dock and app installation.
- How to Work with PDF Files: Reading, Filling and Sharing: How to open, fill in, annotate, merge, split and share PDF files on Windows and Mac using built-in tools and free options.