What are CPU Cores? [All functions explained] 2024

A processor is necessary for every computer to operate, whether a little processor with high efficiency or a massive processor with high performance. The processor, often known as the CPU or central processing unit, is a crucial factor of a working system, but it is not the only one. Most modern processors are at least dual-core, meaning that the CPU has two independent processing cores. But what precisely are processor cores, and how do they work? Let’s uncover!

What are CPU Cores?

A CPU core is like a dedicated processing unit within the actual Central Processing Unit or CPU. Each core is essentially its own independent processor, capable of executing instructions and performing calculations. In other words, a CPU core is a pathway through which a processor runs particular instructions or operations. You can expect better performance and processing power if there are more pathways. 

A CPU can have one or multiple cores. That can have a significant impact on performance, as you can see in our CPU Benchmarks Hierarchy. Most of the processors can divide a core into virtual cores, or threads, using a method called simultaneous multithreading or, if it’s an Intel CPU, Hyper-threading. Different apps utilize numerous threads in different ways.

Function of a CPU Core

A CPU core performs the primary processing tasks of a computer. It retrieves instructions from memory, decodes them, and then executes them. The core manages the flow of data in and out of the computer and communicates with other components, such as memory and storage. The core also performs calculations, logical operations, and other tasks required by the operating system and the applications running on the computer.

In multi-core processors, each core operates independently, allowing the computer to perform multiple tasks simultaneously. This is known as multi-tasking or multi-threading. Each core can run its own set of instructions, enabling the computer to run several applications simultaneously without slowing down. This can improve the overall performance of the computer and can also reduce the time it takes to complete a specific task.

Let’s deeply understand how a CPU performs, or you may say, it repeats the cycle of fetch, decode, execute, and writeback!

1. Fetch

The processor core receives waiting instructions, typically from some type of memory. RAM might be one of these, although modern processors usually have the instructions ready for the core in the CPU cache. The program counter, which serves as a kind of bookmark for the CPU, tells it where the previous instruction stopped and where the next one started.

2. Decode 

It then begins to decode the current command after obtaining it. The processor core must decide how to handle instructions that frequently require different parts of the CPU core, like arithmetic. Each component has a feature known as an opcode that instructs the processor core on what to do with the data that follows it. 

3. Execute

The CPU knows what needs to be done and actually performs it at the execution stage. Several things happen at this point depending on the information entered and the area of the CPU core being used. For instance, the processor’s ALU, or Arithmetic Logic Unit, may do mathematical operations.

4. Writeback

The final stage, known as write back, just stores the finished product back in memory. The output’s exact location depends on the needs of the currently running application. Still, it frequently remains in CPU registers for easy access because the instructions that follow often use it.

Conclusion

The CPU, or Central Processing Unit, is a necessary component of every computer and is responsible for most processing tasks. A CPU can have one or multiple cores, allowing it to perform numerous tasks simultaneously. This improves performance and reduces the time it takes to complete a task. 

Each core is a processing unit within a CPU and operates independently, allowing the computer to perform multiple tasks simultaneously. The CPU cores perform tasks such as retrieving instructions, decoding them, performing calculations, managing data flow, and communicating with other computer components.