how to choose your power supply


How to Choose Your Power Supply

Your PC’s power supply is something that’s easy to forget about.

It’s not flashy.

You can’t impress your friends with its specs.

And it won’t directly make your games play better.

So there’s a very real temptation to just get yourself the cheapest compatible power supply available, and save the rest of your money for the more exciting components.
I mean, who cares about your power supply when you can get more RAM instead?

But, looking to save money by getting yourself a cheap power supply, could end up being a very expensive mistake.

The market for power supplies is flooded with poorly made units, whose capabilities have been vastly overhyped by their manufacturers. In other words, it’s a minefield.

Faulty power supplies aren’t just a waste of money, they’re also dangerous to the rest of your system and can cause serious damage if not identified immediately.first how to choose your power supply

Therefore the risks of picking up a bad power supply are quite serious and can cost you far more
than the price of just replacing the power supply…you might end up having to replace your whole computer!

Additionally, the type of power supply you get will determine what kind of parts you can add to the rest of your PC. If you end up getting a supply which doesn’t have enough kick, you’ll be frustrated if you try to upgrade at a later point and can’t add the ultra-powerful components you want.

With this in mind, it’s worth taking the time to make an informed decision on which power supply will best suit your needs.

This article is here to help you make that choice, we’ll talk you through exactly what you need to look for so you can make an informed decision. When you’re done, you’ll know exactly what makes a good power supply, and what kinds you should be avoiding too.

How Do I Choose What To Get?
Now that we’ve established that getting a good power supply is important. And that picking one doesn’t involve just grabbing the nearest one off the shelf. We can talk about the things you need to consider before buying one.


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(You don’t want this)

The most important thing to consider before parting with any money is whether the unit you’re thinking about buying is reliable. Unreliable units, will cost you time, money and potentially require you to replace your entire PC.

Faulty units have been known to spark, cause lasting damage to other PC components, and on some rare occasions even explode or light on fire. The damage that a faulty power supply can do is potentially very serious and as such reliability is the most crucial thing to be concerned about when thinking about making a purchase.

So how can you be sure which units are reliable and which aren’t?

Well, my first piece of advice would be to stick to well-known brands. While you can pick up power supplies boasting excellent power for very little money, these tend to be from manufacturers with less than stellar reputations.

Trust me when I say that risking it with one of these manufactures is definitely not worth the money you might save. The two brands with the most trusted reputations for making quality power supplies are EVGA and Corsair.

Both have been producing quality units for years, efficiency certifies their units with the 80 Plus accreditation and offers lengthy warranties depending upon the model you buy.

My second piece of advice would be to read some reviews, there’s nothing more important that being informed! We’ve got plenty of thorough articles reviewing our favorite power supplies so take a look at them and decide which’ll best suit you.


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This is basically the amount of power that the unit can generate. Generally more power is better, but of course, more power is also more expensive. So it’s up to you to work out roughly how much power your build demands and then pick yourself a power supply that can handle that with relative ease, without costing more than you can afford.

Manufacturers often talk about ‘maximum’ output, but this is not the number you should be interested in. Instead, you want to know about a unit’s continuous or sustained output. Maximum output can’t be maintained for long and you want the number that the supply can handle for a prolonged period of time.

The best thing to do is to leave yourself a little growing room with regard to the amount of power your unit can produce. Not only will your unit operate more efficiently when it’s not having to work at its hardest, but having that extra space will give you the option to add more components to your build at a later point without having to purchase a new power supply.

For those of you who like to continuously upgrade your PCs, you’ll definitely want to make sure you’ve got a decent amount more wattage than you currently need. Because as you add more powerful components, more strain will be placed on your power supply unit. If it’s not up to the job you won’t be upgrading your PC for very long.

It’s always best to ere on the safe side if you’re not entirely sure about how much power your build needs. An overpowered unit can always power your build, even if it’s got more wattage than you strictly need. But the same cannot be said of an underpowered unit. It’s far better to be safe than sorry.

So, if you’ve got a PC build that uses a total of roughly 400 watts of power, then you might do well to get yourself a power supply unit in the 700-800 watts range. This will make your unit nice and efficient while giving you plenty of room to upgrade your PC as you please.

If you (like most people) haven’t the faintest idea about how much power your PC needs, then you can use this handy little tool to calculate it. Just put in all the components your build uses and it’ll add them up and let you know how much it needs. I’d then recommend purchasing something with more or less double that minimum, just to be on the safe side.


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Power efficiency is very important as well. More efficient units will run more cleanly, quietly and smoothly too. They’re made to a higher standard, and are far less likely to cause you problems down the line.

They also produce far less heat and cause the fans to run more quietly as a result. This could be really important for those of you who hate the sound of loud fans while you’re trying to play games.

Efficiency is typically measured via percentage, that is, if a fan has a 70 percent efficiency (this is not particularly good) than 70 percent of its energy is sent to your PC while the remaining 30 percent is lost via heat.

Units with good efficiency will have an “80 Plus” certification, as you may have guessed this means that they’re at least 80% efficient. This is regarded as being a pretty decent level of efficiency, and you probably wouldn’t want to pick up a unit that was less efficient than this.

There are also separate tiers of certification for those models that are more than 80% efficient. These range from Bronze (which usually means an efficiency rating in the low to mid-80s), up to Titanium (which hovers around the 90% mark).

Generally, it’d be much preferable for you to pick yourself up a more efficient model than a less efficient one, although there is the inevitable trade-off in price. With more efficient units being more expensive than their less efficient counterparts.

A final thing about efficiency which is notable is that a more efficient power supply unit can save you money in the long term. While they are more expensive initially if you use a lot of electricity the costs can quickly add up and having an efficient unit could save you cash.

While it might not be cost efficient to pick up a pricey Titanium just to add a few percentage points of efficiency. You definitely could save money on your bills by at least making sure you pick yourself up a unit in the 80% certification club, particularly if you spend a lot of time using your PC.

Single Rail vs Multi-Rail

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Power on modern supply units is provided by +12V rails. On a unit, with a single rail, all the power will go through that one rail. On multi-rail models, the power is divided between the different +12V rails, with some rails typically having more power than others.

Whether you’ll prefer to have a single or a multi-rail unit basically comes down to personal preference. In the event of some kind of malfunction, multi-rail units are generally regarded to be a little safer.

One of their disadvantages though is that you have to pay attention to which parts of the PC you are powering with each cable, as some may not have enough power to support a particular component. Whereas with single rails it’s just plug in and off you go.

It’s also notable that more powerful models tend to be multi-rail, so if you’re opting for an option with higher wattage, then you might not have a choice when it comes to single or multi-rail.

Modular vs Non-Modular

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A modular power supply is one where any cables that aren’t in use can be removed from the back of the unit. A non-modular power supply is one where the cables are fixed in the back and cannot be removed.

Modular cables are all the rage now, there are a number of reasons why they’re so popular:

Firstly, people like the way they look. Having a ton of useless cables sticking out the back of your PC can ruin the aesthetic of a cool, futuristic gaming machine. Modular power supplies solve this problem by allowing you to freely remove any unneeded cables and store them away in draws or wherever else.

Modular units are also regarded as being a little safer. How many times have you tripped over a stray wire or cable? This is just far less likely to happen with fewer cables about and might be worth considering if you’re accident prone.

Having a modular power supply can also cool the PC by increasing the airflow out the back of the unit. Due to the lack of wires, there’s much more room for cold air to get to the unit and stop the whole PC overheating. This makes your computer cooler and means the fans don’t have to work as hard as well.

Having this extra space at the back can also help to prevent the build-up of dust.

Which is nice because no one wants to see that.seventh how to choose your power supply

Critics of modular units suggest that because you can remove the cables the connections aren’t as strong, and basically say that they’re a silly fad. There is something in that, as cables which are permanently connected are just going to be more efficient than ones that can be easily removed.

Modular power supplies also tend to be more expensive than non-modular models, which might put you off if you’re looking to save a little money.

Ultimately, there’s no wrong answer here, and whether you get a modular or non-modular power supply just comes down to personal preference really. If you dislike seeing plenty of cables and want your build to look clean and aesthetic, then you’ll probably benefit from picking up a modular power supply.

If however, you tend to lose cables and aren’t really bothered about the way your power supply looks (I think this is probably most people) then you’ll probably prefer to get yourself a non-modular supply and save yourself some hassle instead.

These are the main things you need to consider when picking out a power supply. As long as you get these right, any unit you pick up will be good enough to suit your needs.
If you’re interested in what we think are the best power supply units take a look at our reviews.

What power supply do you use? Are there any you recommend? Let us know in the comments below!