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External Power Supplies: Are They Worth It? (Pros & Cons)

Exploring the idea of adding an external power supply to your PC’s arsenal?

It’s easy to start planning out an awesome new PC build (or an upgrade to an existing build) with fancy, high-powered components. Who doesn’t love a beefy CPU, GPU, motherboard, etc?

But with all that fun stuff to shop for, it’s easy to overlook the thing that all of those individual pieces depend on: the power supply (PSU).

Now, all prebuilt PC’s come with their basic internal power supplies. Obviously, as this is the thing plugged into your wall and connecting your PC to electricity.

Sometimes that simple preexisting power supply is all that’s needed. But the more you modify your PC, the more power you will require to keep your PC running at the level you’d expect it to.

When that happens, you can either start planning an internal PSU swap, or, (especially if you are using a laptop), a handy external power supply.

This quick guide will tell you everything you need to know about the pros and cons of external power supplies. We’ll also help you determine if an external PSU is the right fit for your needs.

Do You Really Need an External Power Supply?

External power supplies are definitely worth it for anyone looking to add beefy components to their system but lack the internal power supply to properly do so. This is especially true laptop users or anyone adding a big GPU that may overwhelm an existing power source.

An external power supply is also helpful for simply taking some of the pressure (and therefore heat production) off of an overworked internal power supply.

So, is your external power supply going to help support your graphics cards? Is it going to help an additional audio interface?

Something like one of these bad boys isn’t running on a baby PSU. Jack Skeens / Shutterstock

When choosing your power supplies, you need to know what you are looking for as you can easily mismatch your system if you just follow the basics of wattage numbers alone. You also need to consider what you are getting it for.

All of your major components require sufficient power to run properly and without it, plenty of issues can arise.

When you start shopping for your supply, you should note what the output voltage and current is and that is generally listed on the label of the device. If these are mismatched, you are generally going to run into problems unless you get really lucky.

You also should consider the cooling systems that each of the power supplies require as some might need some type of fan or liquid cooling to keep them operating properly. Most integrated systems have something like this, but not all external PSU’s do, so it is worth looking into before making your decision.

If you’re confused about how much voltage you really need for a certain GPU, take a look at this basic guide from Lumion.

Benefits of External Power Supplies

Voltage Reduction

If you are using your computer’s standard power supply, everything should work just as intended as long as the basic system you have bought or built stays intact. However, PC users love to modify their systems and when higher quality equipment begins being used, that means that there will now be higher requirements from your power supply.

When that happens, your voltage becomes increased and when too much voltage is used, problems can arise. The remedy to this of course is to add an external power supply.

Taking some of the voltage off your main power supply will create a much safer computer environment to use, as the low voltages will keep things running more stable for far longer.

Internal Heat Reduction

When you are using a PC and have multiple programs running at once things can get awfully hot under your desk. While you may think that this heat is coming mostly from other components, the main reason for the heat is that your power supply is getting overworked.

An external power supply will help take that stress of of your main power supply and instead spread out amongst the two, which can cause the heat buildup to lessen considerably. When this happens, you cool off your system overall and, considering heat it one of your PC’s biggest detriments, that is a great benefit to have.

And don’t get us started on the chassis designs from certain laptop manufacturers. Too often, marketing dictates a chassis design that crams components into a shape that is horrible for actual performance.

Laptop Overheating and Frying an Egg
Don’t heat your laptop heat up like a griddle.

This almost always leads to major overheating.

External PSU’s can help keep that heat away from the most valuable pieces of your system.


Perhaps the most convenient thing about external power supplies is that they are far easier to replace than any other kind of power supply.

If the internal power supply fails, to put it plainly, you are in trouble. Replacing an internal PSU is an entire process that can involve sending a PC to the shop or becoming a headache of a DIY project for an unexperienced user.

Luckily, if you use an external power supply, you will have an easily replaceable piece of equipment that is as simple as unplugging one and plugging in the other. That ease of use is one of the biggest benefits of using an external power supply.


For laptop users, external power supplies are the norm, but a lot of times the power supply the laptop comes with is not efficient enough especially when it comes to a gaming laptop.

With an external power supply, you can easily transport these around wherever you’d like and the weight of the device isn’t much more than a pound or two extra to carry.

Drawbacks of External Power supplies

General Heat

While these power supplies can help reduce the heat that is carried within your PC, more heat will generally be created in general by the use of an external power supply.

So more wires and more heat, either near your monitor or under your desk.

While that heat is spread out with the external power supply, it is still one more piece of equipment that can get hot and potentially cause issues (or just make your room uncomfortable), so consider the space available to accommodate such things.


As with all pieces of PC add-ons, power supplies will cost you a little bit. They are not the most expensive, but the more wattage you require, the more the price will drive up and that is something to keep in mind when you’re in the market.

Risk of Choosing Wrong

We only mention this because we’ve seen it happen quite often in regard to power supplies, external and internal alike.

Always make sure you’ve done your research and crunched the numbers for the type of voltage your system will demand. Account for every component within your PC that will draw from the power supply.

Choosing the wrong PSU will result in an unstable environment at best and an unusable PC at worst. You also run the risk of damaging your system if you don’t have things matched up correctly.


Again, when choosing your external power supply, you can’t just go out and select the most expensive one or the coolest looking one. You have to consider what your power requirements are and what is being powered.

There is also plug type to consider for power supplies. Do you need the wall plug style, or one that utilizes a USB? Will it be a universal plug for travel or just one that will likely not be removed once you plug it in?

Final Tips & Recommendations

When it comes to powering your computer to the best of your ability, external power supplies are as good as it gets when it comes to versatility. Although they can have their share of problems, the benefits greatly outweigh the issues and make it an almost necessary component of any heavy-duty PC build without adequate internal power.

The price is usually manageable as well, so this can be one of the few items that you can buy to add on to a PC that doesn’t cost you a fortune to buy.

Like any major PC add-on, this is a product that requires heavy research before picking. Even the smallest mismatch can cause huge issues for your PC in the short term and some potentially permanent damage in the long term.

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