What's inside of a PC?

Viltzu - July 12, 2026 - Tutorial
Tags Hardware,

Banner image: andreas160578 - Pixabay

We use computers more and more in one form or another (even your smartphone is a type of computer), but have you ever looked inside of your computer and figured out what parts are in there and what they do?

This blog post is meant to be a very simplified introduction to the typical hardware included in a computer, and we will go over the function of these parts on a very surface level. The idea for this came to me when I recently upgraded my gaming PC and had many of the components in my hands. Nowadays, many of the devices we own are not meant to be opened and taken apart, so I am not sure if many of you have looked at the different components inside your devices. From a cybersecurity perspective, hardware security at a component level is not that common of a threat compared to software and login information. However, I still believe that cybersecurity experts should be aware of hardware-level threats—even though we'll discuss that more in upcoming posts. The examples and tips given in this post are heavily focused on gaming since it is a dear hobby of mine, so I try to write this post to be informative and also helpful for those who are getting into the world of PC gaming.

To narrow the scope of this post even further, I'll be talking about typical consumer gaming desktop PCs. These PCs usually come in four sizes, which is a good starting point when you are building your own PC from separate components:

Full Tower: Fits everything, including E‑ATX motherboards and giant GPUs.
Mid Tower: Fits ATX and below; the most common choice.
Mini Tower: Fits mATX and ITX.
Mini‑ITX Case: Fits only Mini‑ITX

Your motherboard will set the minimum size required for your PC case, and your other component choices and priorities will determine how big (or small) you should go.

Okay, now we know that the motherboard is a critical component in a PC. How about those other parts? What parts do you need to get to assemble a fully working PC? Here is a list of parts which I got for my gaming rig:

Case
Motherboard
CPU (Processor)
CPU Cooler
GPU (Graphics Card)
RAM (Memory)
Storage (SSD and NVMe)
Power Supply (PSU)

In the past, there was usually a need for a separate Wi‑Fi card/Ethernet adapter and a sound card, but these are typically included in modern motherboards. Your PC also needs an operating system, but we are focusing on hardware this time, so we'll leave that out for now.

Now we have a list of the parts that your PC has, but what do they actually do in a computer? We can skip the function of the case, because its role is basically just to hold your components inside while providing good airflow and keeping components safe from dust (and making your PC look cool and aesthetic, if you are into that).

What Do These Parts Actually Do?

Now that we have our shopping list, let's break down what these components actually do. To make it easy, you can think of a PC like a digital office space.

Motherboard: The Office Building & Highways

If your PC components were people, the motherboard is the building they all work in, complete with the hallways and electrical wiring that connect them. It is a massive circuit board that doesn't do much calculating on its own, but nothing can talk to each other without it. Every single part—from your giant graphics card to a simple USB mouse—plugs directly into the motherboard.

CPU (Processor): The Boss

The Central Processing Unit (CPU) is the absolute brain of the operation. In our office analogy, this is the hyper-efficient boss sitting at the main desk. Every time you click a mouse, launch a game, or load a webpage, the CPU is the one executing those calculations. For gamers, the CPU handles the physics of the game, the AI of the enemies, and tells the rest of your components what they should be doing next.

CPU Cooler: The Personal Assistant with a Fan

CPUs get incredibly hot when they work hard—hot enough to literally cook themselves if left unprotected. The CPU cooler (which is either a big metal heatsink with a fan or a liquid cooling loop) sits directly on top of the processor to pull that heat away. Think of it as a dedicated personal assistant standing over the boss's shoulder with a giant fan, making sure their brain doesn't overheat and crash the system.

GPU (Graphics Card): The Studio Artist

While the CPU is the brain, the Graphics Processing Unit (GPU) is the dedicated artist. Modern video games require billions of pixels to be colored and rendered every single second. The CPU handles the logic of the game, but it hands all the visual heavy lifting over to the GPU. If you want high frame rates, crisp textures, and smooth ray-tracing in your games, this is the component doing 90% of that visual work.

RAM (Memory): The Desk Space

Random Access Memory (RAM) is your computer's short-term memory. Imagine it as the physical surface of the desk your CPU boss is working on. When you open a game or a web browser, the computer loads those files out of permanent storage and dumps them onto the RAM desk so the CPU can reach them instantly. The more RAM you have, the bigger your desk is, meaning you can run more programs at the same time without the system slowing down. Crucially, RAM clears completely every time you turn off your PC.

Storage (SSD / NVMe): The Filing Cabinet

If RAM is the top of the desk, your storage drive is the giant metal filing cabinet in the corner. This is where your operating system, your entire Steam library, and your photos live permanently, even when the PC is unplugged. Nowadays, we use solid-state drives (SSDs), specifically ultra-fast NVMe M.2 drives that plug straight into the motherboard. They act like a filing cabinet with a robotic assistant—retrieving massive game files in seconds rather than the minutes it used to take old, spinning hard drives.

Power Supply (PSU): The Power Plant

None of this matters without electricity. The Power Supply Unit (PSU) takes the high-voltage alternating current (AC) electricity from your wall outlet and converts it into the clean, low-voltage direct current (DC) power that your sensitive computer parts need. From a cybersecurity and safety mindset, a good PSU is your first line of defense; it protects your expensive components from unexpected power surges or short circuits that could physically fry your hardware.

The Rookie Mistakes and Common Compatibility Traps

When you buy a pre-built PC, someone else has done the math to make sure everything fits and works together. But when you are sourcing parts yourself, it is easy to accidentally buy components that simply refuse to talk to each other—or worse, physically won't fit.

Here are the most common compatibility traps to avoid before you hit that "buy" button:

1. The CPU and Motherboard Mismatch (The Socket Trap)

You can’t just buy any CPU and slap it into any motherboard. Both Intel and AMD change their physical socket designs every few generations. If you buy an AMD processor, it needs a motherboard with a matching AMD socket (like AM4 or AM5). Furthermore, even if it's the same brand, an older motherboard won't physically accept a brand-new CPU type.

Always check the Socket Type listed in the specifications for both your CPU and Motherboard. If the letters and numbers don't match exactly, they won't fit.

2. Underestimating the Power Supply (The Wattage Math)

Your components—especially that beefy new graphics card—hungry for power. If your parts collectively demand 650 watts of power under load, and you bought a cheap 500-watt power supply, your PC will instantly crash, restart, or refuse to turn on the moment a game gets intense.

Use a free online outerVision or PCPartPicker wattage calculator. Plug in your parts, see the estimated draw, and give yourself a 150 to 200-watt buffer. If your system needs 550W, buy a 700W or 750W PSU. It keeps the system running cool and leaves room for future upgrades.

3. Case Clearance (Will it Actually Fit?)

Just because a case says it fits a "Mid Tower ATX" motherboard doesn't mean it fits everything else. Modern high-end graphics cards are absolutely massive—sometimes the length of a ruler and three slots thick. Similarly, large CPU air coolers can be too tall, preventing the case's side panel from closing.

Every case specification list includes a "Maximum GPU Length" and "Maximum CPU Cooler Height" in millimeters. Check those against the dimensions of the card and cooler you want to buy.

4. RAM Clearance vs. CPU Cooler (The Spatial Conflict)

This is a sneakier physical conflict. If you buy large, flashy RAM sticks with tall RGB light bars, and you pair them with a massive, dual-fan CPU air cooler, the cooler might physically hang over the RAM slots and block you from plugging the memory in.

If you want a giant air cooler, look for "Low Profile" RAM, or consider liquid cooler instead, which leaves the space around the RAM completely empty.

Wrapping It Up: The Joy of the First Boot

There is absolutely nothing quite like the feeling of putting all these pieces together, managing the cables, pressing the power button for the very first time, and watching the fans spin to life. Building your own PC turns a generic box of plastic and metal into your machine. You know exactly what went into it, how it works, and how to fix or upgrade it down the road. It can be a little intimidating at first, but taking it step-by-step makes the reward of finally booting up your favorite game entirely worth it.

But now that we understand how these components work together to run our games, it opens up a fascinating, often overlooked question: How secure is the physical silicon inside our rigs?

While most of us spend our time worrying about software updates, strong passwords, and phishing links, there is a whole world of digital defense that happens at the factory level. In my next post, we are going to dive into the shadowier side of computer components—hardware-level security threats. We will explore how physical vulnerabilities can exist right out of the box, what "supply chain attacks" look like in the tech world, and why cybersecurity experts need to look beyond the monitor and right onto the circuit boards.

Until then, happy building, protect your digital assets, and I'll see you in the next post!

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Viltzu

OSINT and Cybersecurity enthusiast with thirst for learning more.

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