How to Choose the Best Power Supply for Gaming

how to choose the best power supplyWhen in the process of selecting your parts for a custom gaming build the most often overlooked component is the power supply (aka the PSU). It’s all too common to come across inexperienced first-time builders who don’t take their PSU choice seriously and simply think “Oh it’s just a power supply, I’ll just find the cheapest one that has enough power for my parts and be done with it”. Bad move.

The poor old power supply never gets the respect it deserves. Sure, it doesn’t have a direct affect on gaming performance and it’s not the most exciting piece of hardware, but don’t underestimate its overall importance for your build.

It is a crucial component of any reliable and durable PC build, and buying a cheap no-name low quality PSU to save a few bucks will most likely come back to bite you and cause serious problems for your system. For example, a common problem that can arise due to a poor power supply is random system resets and freezes. Not fun.

The power supply is not only responsible for providing constant stable power, but also to prevent too much current fluctuation and protecting your system from power surges and other electrical danger. You will want to get a reliable, decent quality power supply to support your expensive PC components and to ensure their overall functionality, reliability, and durability.

But how you pick a good one? And how much power do you really need? In this guide to choosing the best power supply for gaming you will find the answers to these common questions and everything else you need to know to make an informed buying decision.

The world of power supplies can be quite confusing for some, so I’ve tried to break it down as simply as possible for you to easily understand exactly what you need to know.

Form Factor and Size

The first thing to be aware of is the form factor and physical size of a PSU. The ATX form factor (ATX12V to be exact) is the standard these days for power supplies and they will fit in any ATX-designed case. Although the width, height, and mounting-screw placement is the same across the board for ATX power supplies, the depth is not set in stone and can vary between different units.

The typical depth of a PSU is approximately 6 inches deep, but units with higher wattages can be a tad deeper. If you’ve got a full tower case this will most likely be a non-issue and any PSU should fit easily, but with some smaller mid-tower cases you may find fitting a larger PSU to be a hassle.

So always be aware of how much space you have in your case and the actual size of your PSU to be sure your PSU will fit comfortably.

power supply depth

How Much Power Do You Need?

The main question you are faced with when choosing the best power supply for gaming is of course how much power do you actually need. Of course there is no set answer and it all depends on your particular component selections and also any potential upgrades you may wish to make to your system in the future.

First of all you should know that there is a difference between the maximum power output and the peak power output of a power supply. The maximum power refers to the continuous or stable power that the PSU can produce consistently, while the peak power is the elevated maximum surge the PSU can produce for a limited amount of time (for example 10 seconds). The important specification to look out for when picking your power supply is its maximum power output, and not the peak power.

A great place to start to work out how much maximum power you need is with online calculators such as the eXtreme Power Supply Calculator. You can Google around and find plenty more if you’re interested. They aren’t perfect and sometimes don’t take into account every single minute detail of your setup, but they give a good general overview of the power your system will require.

If you’re going to use online calculators it would be wise to add roughly another 100 watts to the figure that these calculators spit out for you for a few reasons. Firstly because you don’t want your PSU running too close to its maximum output as this can potentially make it less efficient and shorten its lifespan.

Secondly it’s also better to be on the safe side because you would rather have a little extra power than you need as opposed to not having enough. Lastly, you’ll want to take into account any future upgrades you may make to your system which will require additional power. So for example, if you calculate that you need 525 watts for your build then you should probably get a 600 watt PSU.

If you plan on overclocking any of your components you will also need a tad more power, as it isn’t rare to see power consumptions increase by 50 watts, 100 watts, or even more due to overclocking. It all depends on your particular system, and some of the online calculators will take overclocking into account, but some won’t so make sure you are on the ball.

Once you figure out how much power you need don’t get too excited as it’s not the only thing to consider when choosing the best power supply for gaming. Too many people make the mistake of picking a PSU simply by the maximum power figure, but this alone isn’t enough to determine whether a certain PSU is suitable for your system or not as not all PSUs are created equal.

Rails – What You Need To Know

Power supplies have different “rails” and the invidiual rails of the PSU is an important factor to consider especially if you’re building a powerhouse system. There is one rail that requires the most attention and that is the 12V rail which provides power to your most powerful components such as the processor and video card.

In a typical gaming build the video card will require the most power, and so you’ll want to get a PSU that has at least 24A (amps) on the 12V rail if you have a single mid to high end card, and at least 34A for a high-end SLI or CrossFire video card setup. These are just ballpark figures though to give you a general overview, so it’s best to find out exactly what your video card setup will require.

There are also two different types of PSUs out there, single-rail and multiple-rail. Single-rail PSUs have a single high-powered 12V rail to power all of your components, and multi-rail PSUs have, yep you guessed it, multiple 12V rails each with diffferent amperages to divide power output between two or more rails.

Whether a PSU is single or multi rail doesn’t affect its performance, but the lowdown is if you require a lower-wattage power supply for your system (aka 550 watts or under), the great debate of single vs multiple rails simply does not matter and either type is going to be fine.

On the other hand if you are going to use a more powerful unit with say 650 watts and over a multi-rail unit, although not absolutely essential, will offer an extra layer of protection in the case of a short circuit occurring. When you start getting into massive power PSUs such as 1000 watts and over, multi-rail units start to become a must as there are potential dangers with single-rail PSUs that output so much power.


As I said before, not all PSUs are created equal and some are more efficient than others. A power supply with higher efficiency will not only draw less power but will produce less heat and therefore less noise, and will also save you money on your energy bill.

You’ll want to find a PSU with an 80 Plus rating or better to ensure it is fairly efficient. Th efficiency ratings from least to most efficient are 80 Plus, 80 Plus Bronze, 80 Plus Silver, 80 Plus Gold, and 80 Plus Platinum. If you’re building a very powerful build or your system is constantly in use, you will definitely want to favor at least a Silver or Gold PSU.

80 plus power supplies

Check Your Connectors

Another critical factor in choosing your power supply is making sure it has the right amount and type of connectors for all your devices. All PSUs should have either a 24 or 20+4 pin main power connector that hooks up to your motherboard, and either a 4 or 8 pin 12V connector to power the processor which also connects to the motherboard.

You will need to make sure you have the right amount and types of PCI-Express connectors for the needs of your video card/s , and if you’re running a multiple GPU setup you should check to see that your PSU is either SLI or CrossFire compatible depending on which you are going to use. Although keep in mind that some high-end power supplies won’t have SLI/CrossFire support listed in their specs but they are still capable of powering multi-GPU setups.

Also, check that your PSU has enough SATA or Molex 4pin connectors for your hard drives, optical drives, and other devices. Most PSUs will come with plenty of these connectors, but it’s better to be safe than sorry and checking is especially important if you have a more complex system with devices such as front-bay fan monitors or water-cooling loops.

psu connectors

Modular or Not?

Modular power supplies are a tad more expensive than standard PSUs but come with some handy benefits. They allow you to easily and simply organize your PSU’s cables, with the option of adding or removing cables as needed.

With non-modular PSUs you tend to have some unused cables that you need to bundle up and store somewhere in your PC case, which is not only unsightly and messy but can interfere with airflow inside your case and promote extra dust accumulation. These problems are non-existent with modular power supplies so if you have the money to spend I would recommend getting one.

modular v non modular

Brand Matters

When shopping for PC hardware the manufacturer that you buy from is always an important thing to consider, but with PSUs this becomes even more crucial.

Picking a cheap, generic-brand PSU is asking for trouble and puts all your expensive components at risk. Always stick to reputable PSU brands, and also do your homework on which particular models are best because even quality manufacturers will produce some duds.

Antec, Corsair, Seasonic, Silverstone, CoolerMaster (avoid their eXtreme series!), Thermaltake (only their PurePower and Toughpower series), and EnerMax are some of the best.


If there’s one thing to take from all of this, it’s don’t skimp on your power supply! If you want to build a reliable gaming computer you must install a decent power supply to power your machine problem-free for years to come.

After reading this article you’ll hopefully be confident enough to pick the very best power supply for gaming for your own needs. If you don’t have the time to read detailed specs and wade through technical reviews, I encourage you to check out our top recommended PSUs for various price brackets in the ‘Best Parts’ section of the site.

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