The Brain of a Computer
We use so many terminologies in the world of computers, and one of them which stands out in particular is the CPU. CPU actually stands for Central Processing Unit, and is what we can call the most important part of a computer - its brain.
So what is a CPU?
A CPU is the core of a computer, the main and most crucial part that gives life to all our electronic devices. We also call it a processor because its job is to respond to and process the instructions given by a computer program. The CPU is also in charge of sending commands to the rest of the components of the computer through the motherboard, like how your brain sends commands to the various parts of your body through your nerves.
We find processors everywhere - in PCs, laptops, smartphones, tablets and any form of computer actually. In fact, you would technically be correct if you were to call anything that utilizes a processor in order to function a computer. In fact, a smartphone is essentially a mini-computer.
The two main competitors that make up most of the processor market is Intel and AMD, though its more likely you've heard of the former since Intel has a much greater market share. There are other processor manufacturers of course, like ARM, Apple, Qualcomm and Samsung but they primarily focus on smartphone processors. Unlike AMD and Intel which focuses on developing the fastest processors, these smartphone processor manufacturers have to make the fastest, and smallest processors.
What makes up a CPU?
A CPU is actually made up of billions of microscopic transistors placed onto a single computer chip.
Transistors are basic electrical components that alter the flow of electrical current and are known as the building blocks of a CPU. Since transistors are capable of altering the flow of current, the transistor actually acts like a switch which can switch a signal on or off.
We know that computers operate in binary, so the state in which a transistor is turned on or turned off can be used to represent a 1 or a 0. This is the main reason why transistors are used in processors, because this idea is what allows the CPU to perform mathematical calculations. A series of transistors can also used as a logic gate, allowing for logical operations to take place.
This entire idea is the key to showing us how processor manufacturers keep producing faster and faster CPUs each year. The manufacturers just make smaller and smaller transistors, so they can fit more on the computer chip. More transistors means more processing is able to take place.
Back in the 1978, Intel developed a processor known as the Intel 8086 that had 29,000 transistors. Well, Intel's Core i7-8086K processor that was released in 2018 had around 3 billion transistors. That's about 100,000x the number! As of September 2020, Apple just announced their A14 Bionic Chip which contains 5nm transistors. They claim that the chip holds 11.8 billion transistors. Wow.
Fun fact, there is an observation known as Moore's Law that describes that the number of transistors doubles about every two years. It's a real thing, though who knows how long it'll continue to go for. There's gotta be a limit... right?
Moore's Law visualized.
But what about Cores? Clocks?
You can imagine the multiple cores of a modern day CPU to essentially be multiple CPUs crammed into a single chip. The idea of multiple cores basically allows the CPU to perform multiple instructions at once. Low end CPUs are typically dual core, but higher end CPUs these days go up to 10, or even 12 cores in some cases.
Clock speed on the other hand, denotes how many instructions the CPU can handle per second (hence why the figure is represented in GHz or gigahertz). One might assume that a CPU with a higher clock speed is always better, but that is often not the case. A CPU with a higher clock speed can have less cores and less transistors i.e. a 4GHz processor from 2012 could be much slower than a 2.5GHz processor made in 2020. So don't be fooled by these numbers!
Modern day processors utilize multithreading, a technology that speeds up processors even more. It's not too difficult to understand. Basically, a typical single CPU core can perform only one line of execution at once. We call these lines of execution 'threads'. Multithreading is essentially a CPU core capable of performing two threads at once, allowing for improved multitasking.
That's it from me about CPUs. I hope this article was able to give you an insight about what CPUs are and what they are made of. If you're planning to get a processor for building a new PC, hopefully this helps you clarify some terms that can seem overwhelming at first. Perhaps I should create a guide for selecting PC parts next time around. Who knows, we'll see!