Alister Education / Computer Education / CPU and Processing
COMPUTER EDUCATION · LESSON 03

CPU and Processing

Learn what the CPU does, how instructions are processed, what CPU cores mean and why clock speed is not everything.

BeginnerHardware7 min
CPUfetch • decode • executeDATARESULT

What is a CPU?

The CPU (Central Processing Unit) is the main processor that executes instructions and performs calculations in a computer.

It is often called the "brain" of a computer as a simple analogy, but remember that a CPU does not think or understand like a human brain. It executes machine instructions.

What does the CPU do?

Fetch

Gets the next instruction from memory.

Decode

Interprets what the instruction requires.

Execute

Performs the required operation.

Store result

Places results where the system can use them.

CPU cores

A modern CPU may have multiple cores. Each core can execute instructions, allowing the processor to handle more work concurrently. More cores can help with multitasking and software designed for parallel work, but performance depends on many other factors too.

Clock speed

Clock speed is commonly expressed in GHz. It describes the frequency of the CPU's clock, but it is not a complete measure of performance. Architecture, core count, cache, power limits and the workload also matter.

Remember: CPU performance cannot be judged from GHz alone.
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