If you’re reading this you’re most likely doing so on a computer. Computers are now such a fundamental part of everyday life that today we more or less take them for granted. From browsing the web or playing a game, to writing your first piece of code or running a machine learning algorithm, the remit of modern computers is incredible, particularly in light of what can be accomplished with their help. Computers become an even more powerful tool when you understand how they work.

But what actually goes on under the hood of a computer to allow them (and us) to do so much?

If you’ve ever found yourself asking (or have been too afraid to ask) how computers work, then this guide is for you.

Read on to learn everything you need to know to understand and talk about the hardware that makes all of the digital magic happen.

Different Types of Computers

Computers come in many different shapes and sizes. It doesn’t matter whether you’re talking about the smartphone in your pocket, the laptop on your desk, or the electronic brain inside any digital device out there, they’re all computers.

The main types of computer that we come into contact with on a daily basis fall into three different categories: personal computers (desktop computers and notebooks), smartphones and tablets, and embedded computers (the computers found inside devices and machines like modern cars and smart appliances).

Desktop and Laptop Computers

For the purpose of this guide, we’re going to be looking primarily at the humble personal computer.

These machines are probably what you picture when you think of ‘computer’ and on Elle Knows Machines this is where most (but not all) of the action takes place.

Desktop and notebook computers are primarily used for carrying out productivity tasks, accessing, creating, or manipulating text, image, and sound files, for general entertainment, and for browsing the internet.

Performance and computational power are determined by the components that go into each individual computer and the ability to quickly process information and render intensive graphics usually distinguishes higher spec’d personal computers from lower-end machines.

As a very general rule of thumb, desktops tend to be more powerful than notebooks and laptops. While higher priced laptops are rapidly closing this performance gap, the cost effectiveness of a high-spec desktop computer usually beats the laptop equivalent. What laptops lose in this trade-off they more than make up for in portability – something that isn’t an option for heavier and immobile desktop PCs.

The Main Components: Hardware

If you were to look inside of a computer you’d see circuits, chips, wires, plugs, and a lot of general electronic stuff.  This is all what’s known as the machine’s hardware.

Hardware are the physical components that make the non-physical software (the computer programs or code) actually happen in the real world. While what computers do is really complex, understanding how, why, when, and where they do it isn’t.

Let’s lift the lid and see what’s inside.

How Computers Work Main Components Elle Knows Machines

Each individual component in a computer is a crucial part of the whole and while they all combine to make your machine complete whatever tasks you have lined up for it, they all carry out very different jobs.


The motherboard or ‘mainboard’ holds all of the computer’s components. Essentially a circuit board that the CPU and other components are arranged on, the motherboard brings all of the component together and can be found in everything from smartphones to desktops.

The motherboard is colloquially called the ‘backbone’ of the machine as it’s the component that contains all of the slots and inputs for attaching other components. It also ensures that all of the different components can communicate with each other.

On its own, the motherboard is nothing more than a complex circuit board. It also does no processing itself, instead relying on other connected components (which slot into it) like the CPU and GPU that handle the actual computational work. Nevertheless, the motherboard is not a simple component. As it needs to choose and orchestrate multiple components flawlessly, the intricate infrastructure designs that goes into the board are some of the most sophisticated in the world of electronics.

A motherboard is very easy to spot – it’s the largest printed circuit board (PCB) inside the computer and is covered with connectors, chips, and slots which the board.

Beyond just a piece of hardware, the software element of a motherboard – known as the BIOS or UEFI – often plays a major role in just how good a board is. The BIOS helps the motherboard to iron out small wrinkles or bugs in hardware and in the case of PCs and laptops, allows users to access and manually tweak settings for customizing the performance of the computer, should they want to.

Central Processing Unit (CPU)

The CPU (also sometimes referred to as the ‘Processor’) carries out the instructions in programs and applications. If the motherboard is the backbone of a computer, the CPU is very much the brain that makes everything happen.

The CPU can be thought of as the master chip of the machine that’s responsible for controlling all of the other parts of the computer, receiving instructions, deciding which of its circuits to use and when to use them to carry out these instructions. The CPU takes its instructions in binary (that’s 1’s and 0’s) and works through them one by one, executing them in sequence and one at a time (in serial). The time taken to receive and execute an instruction is known as one ‘cycle’ of processing time.

In a typical CPU, billions of cycles are carried out every second.

Of course, we don’t write out instructions to computers in the form of billions of 1’s and 0’s as if we did, we’d be at it for a very long time. Instead, we write algorithms and software in high level programming languages (like Python) which the computer is then able to translate into binary machine language and get to work carrying out the instructions.

Graphics Processing Unit (GPU)

You may have heard of a graphics card (aka video card) at some point in the past. If so, this is exactly what we’re talking about when we refer to GPU or ‘Graphics Processing Unit.

GPUs were initially designed to render the graphics of intensive applications like games (hence the name). While this is still a huge part of the story thanks to the rise of things like VR and ever more graphically-demanding games, over time, the remit of the humble GPU has moved beyond the entertainment arena thanks to the ability of these devices to carry out processing in a very particular way.

Unlike the CPU, which runs through computations in a serial form (i.e. processing one instruction after another), the GPU does the same task in parallel. Basically, the GPU is able to process simpler and more similar computations simultaneously, whereas the CPU can handle more complicated computations but must do so one after another.

The major upside of the GPU’s superpowers is that not only are they really good at carrying out multiple computations at once, these computations can also be increasingly intensive and the best GPU won’t break a sweat. In heavy-load instances where the CPU is running out of processing steam, the GPU is able to step in and pick up the slack.

The biggest names in the GPU world are Nvidia and AMD and whether you own a GPU, are thinking of buying one for a new PC build, or have used a machine with one installed, it’s almost a certainty that you’ll have used a unit from one of these two names.

RAM (Memory)

The RAM (or ‘Random Access Memory’) is often referred to simply as ‘memory’ and holds the active information on the computer. While the RAM is the computer’s main memory, it is only capable of storing programs and information that are currently being processed – it’s akin to a computer’s short term memory. When it comes to storing information that’s not currently active (and when the computer is turned off), a computer’s dedicated storage or hard drive steps in and store everything.

A key differences between RAM and a computer’s dedicated storage is that, while RAM is about 100 times faster, it’s also only able to store significantly less data than the typical hard drive (like 100 times less). It also loses the data once the computer is switched off.

While some RAM may be more streamlined or have more bits (usually heat-sinks) stuck to the outside, RAM generally looks similar in every instance, no matter how high the memory. Commonly referred to as ‘sticks’ RAM is recognizable in the computer by the long, thin rectangular profile of each stick which slots into the motherboard.

The technical name for the individual RAM modules is ‘DIMMs’ which stands for ‘Dual Inline Memory Module’. Each DIMM is formed of two rows of connector pins at the base of the module (where the RAM connects into the motherboard). These rows are made up of either 168, 184, 240, or 288 pins and allow the RAM sticks to be plugged into the motherboard in the dedicated memory slots, with the average motherboard usually allowing 2 or 4 DIMMs to be connected.

Dedicated Storage (Hard Drive or SSD)

If the RAM is the short term, operating memory of a computer, the dedicated storage or ‘hard drive’ of the machine is where the long term memory takes place. Dedicated storage allows data to be stored beyond just the task being carried out presently so that you can access or ‘read’ it again whenever needed.

This is the fundamental difference that separates a computer’s dedicated storage from the operating memory and without a hard drive, or equivalent long-term storage capabilities of some kind, everyday computing wouldn’t get very far.

There are two main types of computer storage that modern computers utilize, ‘spinning’ internal hard disk drives (or ‘HDDs’) and solid state drives (commonly known as ‘SSDs’).

HDDs are by far the most common storage device on modern personal computers, although SSDs are becoming increasingly popular as prices of the latter continue to fall and both speed and storage increase.

A key thing to note when talking about how computer storage operates is that the devices both ‘read’ and ‘write’ data.

In the case of an HDD device, a moving arm scans a spinning magnetic disc. Each disc is made up of billions of tiny areas which can have their magnetic charge flipped between positive and negative polarity by the arm. In doing so, each of these minuscule regions can represent a binary state (usually, positive = 1 negative = 0). When spread out over billions of regions, you end up with a digital space that allows for the storage of a lot of digital data. The moving arm in the HDD sends a tiny charge to these individual areas when it is ‘writing’ information to the disk, and scans the disc when it is ‘reading’ information from it.

HDD systems are usually cheaper than SSDs and provide larger storage options than their solid state siblings. The major downsides of HDDs however is that while more cost effective per GB, they can be noisy when operating (thanks to their moving parts), are often slower than SDDs. They can also be less energy efficient.

On the flip side, an SSD tends to be faster when it comes to performance and will also be nearly silent (similar to other solid state storage solutions such as SD cards or USB sticks). The primary downside of SSD systems is that on a cost to storage basis, they tend to be more expensive than HDDs, although this will change in the coming years as the cost of memory continues to fall year-on-year.

June 8, 2019