What is a CPU?
A CPU is the part of a computer that follows a program's instructions in order, billions of tiny steps every second.
1. The part that runs programs
In most laptops and phones, the CPU, or central processing unit, is one part of the main chip. It runs programs, such as apps.
2. It follows a recipe, step by step
A program is a list of tiny steps, called instructions, like a recipe. The CPU is the cook: it follows the steps in order, one after another.
3. Billions of steps every second
A clock inside the chip ticks very fast, and the CPU's work moves forward on every tick. 3 GHz (gigahertz) means 3 billion ticks a second; giga means billion.
4. Many cooks in one chip
Today's CPUs hold several cores. Each core is a cook of its own, so eight cores can work on eight jobs at once.
Words to know
- Program
- A list of steps for a computer to follow.
- Instruction
- One tiny step in a program, such as “add these two numbers”.
- Clock speed (GHz)
- How many times a second the CPU's clock ticks. 1 GHz is one billion ticks a second.
- Core
- One complete worker inside a CPU. More cores can do more jobs at once.
Where you meet it at work
Chip teams set the rules for how fast each core may tick and when it may rest, and the chip follows them while it runs. Faster ticks finish work sooner but use more power and make more heat, so the chip speeds up only when there is work to do.
Check yourself
A CPU runs at 4 GHz. About how many ticks is that each second?Think first, then tap to see the answer.
About 4 billion. Giga means billion.