CPUs (central processing units) are central to any electronic device, but what is a CPU?
We’ve created this guide to explain everything you need to know about CPUs, including what they are, what they do, how they work and more. We also touch on cores, threads, clock speeds and the ideal temperature for your CPU.
Keep reading to learn more about CPUs or visit our high-end vs mid-range CPUs guide to learn more about the different processors available today. We’d also recommend checking out our best lists for the best CPUs, gaming CPUs and Intel processors we’ve tested.
What is a CPU?
The CPU is the main chip in an electronic device responsible for managing and sending instructions to other components. The acronym CPU stands for Central Processing Unit, though this is often shorted to just ‘processor’.
You can think of it a bit like the brain of a device, whether that be your phone, tablet, PC, smartwatch, camera, TV – or even your fridge.
More specifically, a CPU is a complex set of circuitry that processes signals, fetches instructions and executes tasks for hardware and software running on the device.
In smartphones and tablets, the CPU might be located within another chip that handles other aspects such as phone calls, Wi-Fi and GPS. This is called an SoC, or system-on-a-chip.
What does a CPU do?
A CPU’s job is to send instructions to the other components in your PC. This means it plays a crucial part in completing almost any task.
For example, the GPU wouldn’t be able to do its job of generating images without instructions sent by the CPU. The same goes for the NPU – or Neural Processing Unit – where most AI tasks are handled. Without the CPU, the NPU wouldn’t work properly.
How does a CPU work?
The CPU fetches instructions from a computer’s memory before a control unit (CU) within the processor begins to decode and interpret the instructions. The CU determines which addresses and data items are needed for the tasks at hand, before passing the instructions over to another part of the CPU, the ALU (Arithmetic Logic Unit).
The ALU is responsible for tackling arithmetic and logic computations and will carry out the necessary operations. Finally, the output is returned to the memory where it can be accessed by other programs.
This process is repeated over and over again until every task required by a program is complete.
What is overclocking a CPU?
The clock speed of a CPU tells you how many calculations the processor can make per second, with a higher number equalling more calculations. This figure is expressed in gigahertz, or GHz.
A high clock speed is key for tasks that require a lot of processing power, such as gaming and video editing.
Overclocking essentially refers to the act of pushing a CPU’s clock speed beyond its default settings, improving its performance for the above tasks. However, it’s important to note that overclocking requires more power and can make your PC more likely to overheat.
What is a core in a CPU?
Another factor that can affect the speed of a CPU is the number of cores it has.
Most modern CPUs have at least two cores, with many opting for four, eight or more. Each core essentially functions as an individual CPU capable of processing a program’s data simultaneously.
A four-core CPU can double the speed of a two-core one, though it’s important to note that adding more than four cores won’t necessarily improve the performance.
What is a CPU thread?
A thread can be thought of as a virtual version of a CPU core designed to increase the efficiency of the processor. You can typically expect a CPU to receive two threads per core.
Threads, like cores, are key for multitasking and handling heavy workloads.
What is a normal CPU temp?
According to a guide by Avast, a safe CPU temperature for a PC is between 40 to 65°C (104 to 149°F) for a normal workload, or between 0 to 80°C (158 to 176°F) for more intensive tasks such as gaming or editing. Anything above 80°C (176°C) could be cause for concern – especially if you’re not running anything particularly strenuous.
Continuous overheating can damage your computer, so it’s a good idea to keep an eye on your CPU temperature and take steps to keep it cool when needed.
What is the difference between a CPU and a GPU?
The CPU and GPU are two of the most important components in a computer.
The CPU is the brain of the PC, sending instructions to other components, whereas the GPU (Graphics Processing Unit) is typically a lot faster than the CPU and specialises in creating images.
You can learn more about Graphics Processing Units and what they do in our guide to GPUs.
What is a quantum processor?
A quantum processor (QPU) refers to the CPU of a quantum computer. These are computers that use quantum mechanics to perform calculations much faster than your everyday PC.
