Why is it important to have a good one?

As you embark on the journey of building your own PC for the first time, one of the earliest obstacles you may encounter is figuring out what parts you need and what they do. You may be confronted with a storm of confusing acronyms. GPU, ATX, CPU, ITX, PSU, SFX… and so on. For a new builder,  all of these acronyms and part names that are thrown around without explanation can be quite daunting. So let’s start with one of the most essential components for any PC build. The power supply unit, or PSU.

What exactly is a PSU?

The PSU is not really the most glamorous or talked about component, but it is undoubtedly among the most important. The PSU can be thought of like the heart of the PC. Nothing in the whole system will work without a PSU as it supplies power to every other component. A good PSU will keep your PC safe and happy, while a bad one might fry the whole machine beyond repair.

To get slightly technical, a PSU plugs into a wall outlet and converts the AC power supplied to your home into low-voltage regulated DC power to be used by your PC. As such, a PSU does not itself supply power as the name might imply, but rather converts it. Without a PSU, your PC will not be able to get any power and thus will remain a lifeless, useless box. We don’t want that! So, you need a PSU in your PC. But why does it matter which PSU you buy?

Why do I need a good PSU?

Let’s talk a little bit about what could happen if your PSU fails. Sometimes, a failing PSU won’t make itself known for a long time. Other times, alarming issues such as stuttering, blue screen errors, or sudden restarts could be signs that a PSU is going bad. If things get really bad for your PSU, it can accumulate excess heat that leads to smoking, or even a fire. Besides destroying your PC, this is also a major safety hazard and you should do everything you can to avoid this scenario!

So how to ensure you don’t burn down your house while playing your favorite games? It is important to know that the best PSUs are incredibly safe, and while no PSU is perfect and you should be aware of what can happen when a PSU goes bad, if you put time and care into selecting the right PSU for your build, you won’t have to worry too much about starting fires.

How do I choose the right PSU?

The first aspect to consider when buying a PSU should be your wattage needs. Generally, the more powerful your PC is, the more wattage you are going to need. For example, some of the latest and greatest graphics cards come with a minimum PSU recommendation of 850W. It is important to research your components and figure out how much wattage you need, otherwise you might experience crashes or overheating, and generally your PC simply will not work. If you want to check how much wattage your planned PC build will require, we recommend using a power supply calculator such as ours: https://www.coolermaster.com/power-supply-calculator/

Another aspect to consider when buying a PSU is sizing. PSUs come in a few different sizes, with the most common being ATX and SFX. In later articles, we will go into more detail about what exactly those categories mean, but for now just know that ATX PSUs are bigger, and SFX PSUs are smaller. You want to make sure your case can support your PSU. For example, smaller cases are sometimes called SFX cases or mini-ITX cases and they cannot support ATX PSUs as there is not enough space within the case.

You should also take efficiency into consideration. Most PSU manufacturers partake in the 80 Plus voluntary certification program, which rates a PSU’s efficiency level and certifies it according to a 6-tier ranking system including bronze, silver, gold, platinum, and titanium rankings. PSUs with higher 80 Plus efficiency ratings will improve your energy savings and generally come with higher quality internal components.


Now that you know a little bit about what a PSU is and why it is important, you can go about finding the right PSU with a little more confidence. We have discussed wattage, sizing, and efficiency as three major factors to take into consideration when buying a PSU. In the future, we will have more in-depth guides about how to choose the PSU that is right for your build. For now, if you would like more information on Cooler Master’s own selection of PSUs, please visit https://www.coolermaster.com/catalog/power-supplies/. Happy building!

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