The 7 Parts of a Computer: Beginner’s Guide

Written by Azzief Khaliq
Last updated Mar 8, 2022

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parts of a computer

Learning the core parts of a computer and what they do is the first step in your journey as a computer enthusiast. Yes, you can use a computer perfectly well without knowing what any of its parts do. But knowing this information can be useful, especially if you want to build your own computers in the future.

Knowledge is power, as they say; knowing what each part does and how it generally impacts performance can help you decide where and how to spend a limited budget. The seven core parts that we’ll be discussing here are:

  1. The case
  2. The motherboard
  3. The central processing unit (CPU)
  4. The graphics processing unit (GPU)
  5. Random-access memory (RAM)
  6. Storage (SSDs and HDDs)
  7. The power supply unit (PSU)

To be clear, we’re not writing this post to help you choose PC parts or teach you how to budget for your new rig. Think of this as a basic primer before moving on to those more specific topics.

The Case

For any PC, the case is where it all begins. The case holds all the parts of a computer and thus plays a key role in determining the components you can install in your rig.

Cases come in many different sizes and shapes, but four main sizes dominate the market. These are, from largest to smallest:

  • Full-tower
  • Mid-tower
  • Micro-ATX tower
  • Mini-ITX tower

pc case size comparison

Full- and mid-tower cases have room for ATX motherboards, with some even having room for relatively uncommon extra-large sizes such as E-ATX. Micro-ATX and Mini-ITX cases support Micro-ATX and Mini-ITX motherboards, respectively.

The smaller the case, the more limited your choice of computer components. Graphics card length, CPU cooler height, and power supply size are the most significant sacrifices as you go down in size. Some Mini-ITX cases only have room for low-profile CPU coolers, miniature graphics cards, and small-form-factor power supplies. Small cases also limit the number of storage drives you can install.

Cases also greatly influence your internal components’ temperatures. Cases with mesh or vented front panels (like the Phanteks P400A) and unrestricted interiors tend to cool your parts better than those with solid front panels (such as the NZXT H510).

Phanteks P400A Digital

A Phanteks P400A. Source: u/superkamikazee

Graphics cards are relatively temperature-sensitive and will reduce clock speeds the hotter they run. So, it’s in your best interests to keep your PC running as cool as possible for the best possible gaming performance.

Interested in finding out more? Check out our guide to choosing a PC case for more in-depth discussions of PC cases.

The Motherboard

The motherboard is the heart of your system, and all other parts of a computer plug into or connect to it. CPUs socket directly into the motherboard, your graphics card slots into one of the PCI Express (PCIe) connectors, while your storage drives connect via SATA or NVMe ports.

Motherboards generally don’t impact performance unless you plan on overclocking. If you do, then specs like your motherboard’s VRM quality can play a role in how fast you can push your CPU. In most other situations, though, a CPU will perform similarly (if not identically) in different motherboards.

ASUS ROG Crosshair VIII Dark Hero

An ASUS ROG Crosshair VIII Dark Hero. Source: ASUS

But this isn’t to say that motherboards have zero impact on your day-to-day computing experience. Specs such as the number of SATA and NVMe connectors, USB ports, and PCIe slots will determine how many extra components and devices you can install and connect.

There are three common motherboard sizes. Here they are, from largest to smallest:


As you might expect, the smaller the motherboard, the fewer expansion options available. Let’s take SATA ports as an example. A standard modern ATX motherboard usually has six to eight SATA ports. In contrast, a Mini-ITX board (even a high-end one) usually has at most four SATA ports.

So while you’ll get similar framerates and render times regardless of your motherboard, it will directly influence what you can do with your rig in other aspects. The number of storage drives, USB devices, and expansion cards all depend on your motherboard.

If you’re interested in the finer details of selecting a motherboard, our guide to choosing a motherboard is an excellent place to start.

The Central Processing Unit (CPU)

If the motherboard is the system’s heart, then the central processing unit (CPU) is the brain. The CPU executes commands and sends orders to the other parts of your computer; there’d be no way to run programs without it.

So, it shouldn’t come as a surprise that your CPU will have a significant impact on your computer’s performance. However, not every program or workload relies on the CPU in the same way.

Some tasks and programs, such as compiling software, are heavy on the CPU and rely primarily on CPU performance. Here, monster CPUs like the Intel Core i9-12900K or AMD Ryzen 9 5950X excel. On the other hand, games tend to be slightly lighter on the CPU and rely more on our next component, the graphics processing unit (GPU).

Intel CPU

An Intel CPU. Source: Roman Spiridonov

But even if games don’t hammer the CPU quite as much as productivity tasks, it still pays to have a faster CPU more often than not. The CPU has to do all the logic calculations and tell the GPU what to do, so it still plays a significant role in a gaming rig’s performance.

So CPU performance is important overall, although the balance between CPU and GPU power changes depending on what programs you’re running and the things you’re trying to do with your rig.

We’ve got a great guide to choosing a CPU that goes into a ton more detail, so click through if you’re interested in finding out more. We highly recommend reading it, as figuring out specs such as CPU performance can get really complex.

The Graphics Processing Unit (GPU)

The graphics processing unit (GPU), commonly known as the graphics or video card, is one of the parts of a computer that gets the most attention. And justifiably so, as it’s the part that almost single-handedly determines a rig’s gaming performance.

GPUs receive orders from the CPU and translate them into what you see on-screen. Textures, models, lighting, and visual effects, amongst others, are processed and executed on the graphics card. But GPUs also do basic tasks such as sending your Windows desktop to your monitor, so all modern rigs need a GPU of some sort.

The type of GPU depends on what the rig is for. Most gamers opt for more powerful discrete graphics cards that slot into a motherboard’s PCIe slot. However, CPUs like the AMD Ryzen 5 5600G come with reasonably capable integrated graphics solutions.

Nvidia GPU

Two Nvidia GPUs. Source: Nana Dua

A graphic card’s importance for productivity and professional tasks will depend on the program itself. 3D rendering programs like Blender can use modern Nvidia and AMD GPUs to speed up render times significantly, so powerful GPUs remain essential there.

However, programs such as Adobe Photoshop almost exclusively utilize the CPU for most of its heavy lifting, relegating the GPU to the task of sending your computer screen to the monitor. So for Photoshop and other CPU-heavy programs, simple “display adapter”-type GPUs (or integrated graphics) are more than enough.

Random-Access Memory (RAM)

Your computer uses random-access memory (RAM) to store important “short-term” data that the CPU needs to run your programs. The high-speed connection between RAM and your CPU gives the latter almost immediate access to the data, eliminating wait times and ensuring your programs run

While that may indicate that faster RAM is always better, that isn’t necessarily the case. The importance of RAM speed depends on the individual program and workload. Some games like Fortnite, for example, perform better with faster RAM. However, many other games aren’t as fussy as long as you have a modern kit.

Random-access memory

G.Skill TridentZ RAM in MA Modified’s Desk PC Build

Overall, having fast RAM is less important than having enough RAM. Modern programs eat up a lot of RAM—those memes about Chrome gobbling up RAM aren’t a joke—so 8 or 16 GB of RAM is usually the ideal amount for a modern rig. Video editors and professionals will want more, up to the limit of what their programs can use.

RAM is usually one of those parts in a computer that you either pay little attention to or spend a lot of time (and money) trying to get right and optimize. But even if you’re not interested in the latter, it’s still worth reading our RAM buying guide to avoid common pitfalls.

Storage (HDDs and SSDs)

RAM is fast, but it’s volatile. That means any data stored in RAM disappears when you shut down your computer. So it’s not suitable for the long-term storage of files and data. But that’s where storage drives like hard drives (HDDs) and solid-state drives (SSDs) come into the picture.

Storage drives do what they say on the tin: they store your data, including the operating system that lets you use and interact with your computer in the first place. Both storage drive types do the same job, albeit using different techniques.

Hard disk drive

Source: lilzidesigns

Hard drives are older and slower technology that uses magnetic disks and a moving head to store and read data. They have the advantage of availability in huge capacities (like this 16 TB Seagate HDD) but suffer from slow read and write speeds.

Solid-state drives use flash memory (much like SD cards) without moving parts, so they have significantly faster read and write speeds than HDDs. However, they’re still relatively limited capacity-wise and offer less value (in terms of storage per dollar) than HDDs.

The largest “mainstream” SSDs you can buy top out at 8 TB, so HDDs are still the best choice for mass data storage. But in situations where read and write speeds matter (such as load times in games), SSDs are the better choice, even if you have to sacrifice some storage capacity.

Portable solid state drives

Portable SSDs. Source: Jeremy Bezanger

For a more thorough overview of the differences between hard disk drives and solid-state drives, head over to our SSD vs. HDD comparison. It goes into more depth about the differences and where each type of storage drive shines.

The Power Supply Unit (PSU)

We’re done with the components that more or less directly impact performance. However, there’s one more component that plays a big role in the reliability and stability of your computer system: the power supply unit (or PSU).

The power supply unit converts mains power into all the necessary voltages that your computer needs to run. A good power supply won’t improve or worsen gaming performance. But bad (or inadequate) power supplies will arguably have an even worse effect: random shutdowns and possibly burnt-out components.

Power supplies are available in different wattages and efficiency levels. The former is simple and indicates how much power the PSU can provide to your PC. The more power-hungry your parts, the more wattage you need.

Corsair HX850

A Corsair HX850 power supply. Source: Corsair

Efficiency measures how much wattage your PSU delivers compared to what it draws from the wall. The 80 Plus rating system is the industry standard, from Bronze to Titanium. The higher the rating, the more efficient the power supply.

Closing Thoughts

So there you have it: the seven core parts of a computer. From the essentials like the motherboard and CPU to luxuries such as a high-speed SSD, learning the function of computer parts is the first part step toward building your own PC.

Once you’ve gotten a grasp of these components, you can move on to learning how to pick PC parts. It’s a fun journey, and we’re glad you’ve decided to come along for the ride. Have fun!

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