What Is a CPU?

作者：Coursera Staff • 更新于 Feb 15, 2025

Learn what a central processing unit (CPU) is, how it enables a computer to function through the instruction cycle process, and the factors that influence CPU speed.

[Featured image] A person in a blue shirt sits at a desk next to a window and works with code on a laptop and secondary monitor.

The central processing unit (CPU) is a critical hardware component that enables computers to respond to commands. Found within the circuit board of computers, a CPU’s main components include the control unit, the arithmetic logic unit, the registers, and the buses.

In order for the CPU to understand commands, software translates messages into a series of binary codes. The binary code received by the CPU then goes through the three-step instruction cycle:

Step 1: Fetch

The CPU first must fetch instructions stored within the computer's random access memory (RAM). A component of the CPU known as the instruction register stores the instructions.

What does CPU stand for? Does CPU mean RAM?

No, CPU does not mean RAM. The CPU, also known as the processor, gives the computer instructions to perform. On the other hand, RAM is what the computer uses for temporary storage space. The CPU and RAM work together and are important in giving you computing power.

Step 2: Decode

In order to determine what actions to perform, the CPU transfers instructions from the instruction register to the instruction decoder, where it performs a calculation to decode the instruction into signals.

Step 3: Execute

During the final step, the decoded signal travels to specific locations in the CPU, allowing the CPU to execute the desired action. The instruction process repeats itself automatically as the CPU moves on to the next task.

Explore the key terms below to understand further how CPUs function.

Clock speed refers to the speed at which a CPU is capable of functioning and processing commands, and it is influenced by a number of factors. A CPU with more cores is able to process information faster, and modern CPUs typically have multiple cores.

In some cases, however, a higher clock speed doesn’t always equate to a better CPU, since high clock speeds require greater levels of power consumption in addition to causing the CPU to generate heat.

Hyperthreading is an advancement to CPUs that enables a single core to process information faster as if it had the power of two cores. Hyperthreading divides information into multiple threads, allowing the core to process the threads simultaneously.

Another component that influences processing speed is cache memory. The cache contains limited amounts of frequently accessed data, allowing the CPU to quickly use this memory rather than waiting for memory from RAM and process commands faster.

Explore CPU specs, storage, and processor types: Build IT skills on Coursera

If you’re ready to start or continue your information technology career, consider earning a Google IT Support Professional Certificate on Coursera. With this program, you’ll earn an employer-recognized certificate from an industry leader and learn how to perform several IT support tasks, including installing programs, wireless networking, and computer assembly.