How to Upgrade/Install a Power Supply

Let’s learn more on how to properly upgrade/install a power supply.

The power supply otherwise known as PSU is the life force of all computers. It gives every piece of hardware the ability to function.

Think of this task as the heart that pumps blood throughout your body, the PSU outputs electricity that gives your computer life. Once the power supply gives out, nothing will function for any computer. In this case, we need to upgrade/install a power supply.  

In need of a new one?

Before we jump into purchasing a new power supply, consider a few things before getting started. Power draw, wattage requirements for your components, a power supply that has cables that fit the computer parts, and what model of PSU will fit the PC case. 

Once all of the information is taken/written down, we can purchase one, install it, and be on our way. Since this part of the computer is connected to multiple parts, we need to take steps to break down this process of how to upgrade/install a power supply. 

Picking a New Power Supply

The joy of picking and choosing, as well as life long decisions. 

Choosing the right power supply is essential for making sure your computer runs well. Without an adequate supply of regulated electricity, the computer might suffer the consequences of performance issues, for example not even turning on. 

How Much Power Do I Need?

The power of adulting. Oh, the excitement! (Total sarcasm intended)Carry On!

The amount of energy a power supply delivers is measured in watts. They generally provide from around two hundred for the smallest and most efficient machines to over a thousand (one kilowatt) for the biggest, beefiest gaming and media desktops. 

Determining how much power you need is a matter of adding up the power draw from all of the components. The biggest two power draws on a computer are typically the CPU(Processor) and GPU(Graphics Card). 

That’s assuming you use a graphics card. Not all computers have a separate card dedicated to graphics. 

Sometimes a computer might have a discrete card that is low power enough to draw its electricity directly from the motherboard. But if your computer is built for gaming or even some media editing duties, you’ll need to account for it.

Other components also draw power, including hard drives, optical drives, and cooling systems like fans or radiators. These typically require much lower power, and can usually get away with rough estimates.

If you want to estimate the power requirements, look at the specifications of each component in particular.

For example, on Intel’s website we see that the processor draws an average of 91 watts under high load. 

Example Power Draw For A Computer

Here is a list of the power requirements for a test build I created for all the components:

  • Processor: 95 watts
  • Graphics card (Radeon RX 460): 120 watts at peak
  • Motherboard: 40-80 watts
  • RAM: under 5 watts per DIMM(Dual Inline Memory Module) – estimated 20 watts for our build
  • SSD(Solid State Drive): under 10 watts
  • 120mm fan for CPU cooler: under 10 watts

Based on these figures, we can estimate that this computer won’t use more than 350 watts safely under its full load. Some graphics cards recommend at least a 400-watt power supply. This is because the GPU is the highest power draw of every part of the computer. 

Before moving onto the next step keep this in mind. Retaining a margin of error is a must-have, not to mention the fact that having a little extra power gives additional room to add more components in the future, like extra storage drives or cooling fans.

He-man inspirational moment: I have the power!

If you’re not sure about a computer’s power supply needs, there is an online calculator you should check out. This will take you to Extreme Outer Vision website that will help you use a calculator to see how much power you need for your computer.

Just plug in the desired components and it gives you a recommended wattage. Add a little bit for a safety margin, and there is all the wattage your PSU needs to deliver a stellar performance!

What is a Form Factor in a Computer?

In computers, the form factor is the size, configuration, or physical arrangement of any device like the power supply. 

The term is usually to describe the size and/or arrangement of a device, a computer case or chassis or one of its internal components such as a motherboard or a power supply in this instance.

What Form Factor Should I Choose?

After you’ve determined how much power you need, you’ll need to find a power supply that physically fits in your computer. There are a few sizes for power supplies, and chances are, at least one of them will fit the case you are using.

The most common size for power supplies is “ATX”. It is a standard size for a majority of computer towers. If you choose an ATX PSU, you need to make sure the tower of the computer is also standard size. 

Most of the ATX models will range anywhere from 300 watts up to 850 watts.

There are a few irregularities with the ATX model. Some of the power supplies are longer than normal, stretching to eight or ten inches long, but keeping their width and height standardized. 

These are the monsters that can power high-end Processors, multiple Graphics Cards, arrays of storage drives, and a computer full of cooling fans, stretching from 900 watts up to 1200 watts and beyond. 

But didn’t we cover they only go up to 850 watts?

Well, these PSUs are the irregularity. Sometimes these extra-large ATX power supplies are needed for computer builds, will have trouble fitting into a standard case, and require oversized computer cases. 

These are used for gaming rigs that require more power, possibly for some streamers or media editors. Unless you specifically bought or built the computer to have a ton of power, you probably don’t have to worry about it. 

If you do have a monster computer, look up the case’s specifications: it will let you know the maximum dimensions of the location to which the power supply will sit.

Some More Info on Form Factors

On the opposite end of the spectrum, some cases are too small for even a normal-sized ATX power supply. These include “small form factor” cases and those that are meant to hold smaller standardized motherboards, like Micro-ATX and Mini-ITX. 

These power supplied generally top out at around 400 watts, though some more expensive and more powerful units are made.

Image Credit: Tom’s Hardware

SFX and TFX power supplies are for small, compact cases.
If you go even smaller, things tend to get non-standardized, and you’ll want to look for a replacement for your specific model. 

If you’re upgrading because there is not enough power in the current power supply and your case won’t accept anything bigger, you’ll likely need to upgrade said case as well, and move all of the other components into it. 

At this point, a complete computer replacement might be more practical.

What Cables Do I Need?

The cables that run from your power supply to the various components in your computer usually come with the PSU, but there are three crucial types you want to double-check for compatibility with your specific PC:

Main Motherboard Cable

Main motherboard cable to PSU
Image Credit: Amazon
  • This cable runs directly from your power supply to your motherboard, and plugs into the board using 20 or 24 pin plug. 
  • Most high-end power supplies have 20 pin plug, plus an additional 4 pin plug so that you can plug it into either type of motherboard. It’s worth paying attention to how many pins your motherboard uses and making sure you buy a power supply that can handle it.

CPU Cable Connecting to Motherboard

CPU cable to motherboard
Image Credit: Amazon
  • This cable also runs to the motherboard, but is used to power your CPU. These come in 4, 6, and 8 pin varieties. Some high-end motherboards offer combinations (like an 8-pin and additional 4-pin connection) to spread out the voltage, but these are rare.

GPU Power Cable

cable from power supply to GPU
Image Credit: newegg
  • These cables run from your power supply directly to a graphics card. If you don’t use a graphics card, or if the card you use doesn’t require separate power, then you don’t need to worry about these. 
  • Graphics cards that do require separate power use either a 6 or 8 pin plug. Some of the bigger cards even require two cables. Most power supplies powerful enough to run gaming rigs offer a pair of cables for your graphics card (even if you only need one of them) and offer a 6 pin plug with an additional 2 pin plug so they can accommodate whatever card you use. This is important if you want to build a gaming computer. 

You’ll also need cables for other components: hard drives, optical drives, case fans, and so on. Modern storage and optical drives use standardized SATA power connections, and every modern power supply includes them. 

Case fans typically use 3 or 4 pin plugs, and again, modern power supplies usually come with at least one of these. 

Info overload I know but knowledge is power.

What About the Efficiency of the Power Supply?

Modern power supplies include an efficiency rating, usually indicated by the “80 Plus” voluntary certification system. 

80 plus power supply efficiency ratings

This indicates that the power supply consumes no more than 20% over its output wattage; if you buy a 400-watt power supply, at full load it won’t consume more than 500 watts from your home’s electrical system.

Compliance with the 80 Plus system is indicated by a sticker on the power supply and usually advertised as a feature on the box or online listing. 

There are different grades of the 80 Plus sticker: standard, bronze, silver, gold, platinum, and titanium. Each higher-level indicates a higher point of efficiency, and generally a higher price. 

Almost all power supplies sold at retail reach the minimum 80 Plus requirement. The power supply’s efficiency rating won’t affect its output. 
If you buy a 400 watt supply, it will deliver 400 watts to your computer, no matter how much it draws from the power outlet. 

But those wishing to save some money on their power bills in the long term may want to shop for higher-rated supply. 

Now that you know more about power supplies, we can make an informed decision when it comes to choosing a PSU. But now let us begin the processes to upgrade/install a power supply.


Steps to Upgrade/Install a Power Supply

  1. Find a work area that is safe for your computer
  2. Gather Tools as Needed
  3. (Optional) Back-Up Files
  4. Removing Old Power Supply
  5. Installing New Power Supply
  6. Double Check everything is plugged into the Power Supply

Ready to get started? I hope so since you’ve gotten to this point already.

Step 1: Find a large flat work area that is also safe for a computer

large flat work area

The first step is creating a flat workspace that is safe for a computer; it could be a table or a hardwood floor. Anything so you don’t lose parts and to help stay organized when taking apart the computer. 

The steps it takes to upgrading/installing a Power Supply are very short. The longest part of the process is making sure everything is unplugged from the power supply. 

Having a safe flat surface to work with will give you the ability to scope around the entire computer. It will enable you to get a good visual of all the plugs connecting to the power supply. 

I like to use a larger wooden table as its a flat surface that you can easily maneuver around the computer.

Keeping the process short and sweet by staying organized will give you the best success here. With any process, you need to make sure you have the right tools.

Simplicity is key!

Step 2: Gather Tools Needed

This is the point where you need to gather all the tools that might be needed. Of course you might be ahead of this step and came prepared. But for those who didn’t get the tools, the list is short as you potentially don’t have to take anything apart. 

This depends on how the power supply is mounted onto the computer and if you need to take anything apart to get it out. 

Having said this I would come with a Phillips screwdriver, plastic trays for screws if there is any and an anti-static band just in case you happen to touch the inside of the computer.

You can use an anti-static band, or just ground yourself every so often. This can be utilized with anything, from a sink faucet to the outside of your computer case, so long as it’s made of metal. 

I have never had my hardware fail on me due to not using one while tinkering with the hardware, but you can never be too safe.  

Stay Organized

Lastly, a useful item that I mentioned earlier to keep a space organized, such as a bowl to hold loose screws. You could even use a plastic tray. 

plastic trey

I found that a tray was more versatile as it was flat and didn’t force the screws to go to the middle of the bowl; while a bowl does help to contain a mess it’s harder to see all the loose screws and smaller hardware. 

A tray allows us to see every piece while containing that mess. It is all preference, but at the end of the day, it is what you feel works best for you!

Also, something soft to lay the computer cases outside walls on. This is because I know my case includes a glass wall and not wanting that to be scratched or dinged. 

Hardwood floor is best to work on, it’s better to avoid rugs and carpets. And finally!

Work smarter not harder!

Step 3: (Optional) Back-Up Files

If you already know how to complete this step or aren’t worried about losing files, skip to step 4! 

This is optional as some people don’t mind losing what they have on the computer. I don’t believe you will lose any files while you upgrade/install a power supply. 

However, if you are nervous about something going wrong, I left multiple steps here so you can back-up your files.

Some folks are not as partial to losing documents, pictures, or overall apps on a computer. 

But if like millions of others out there who store and hold on to valuables such as old family photos, important documents, etc. This will be the most useful information to use!

The best way to back up your files is to have an external hard drive such as a USB. Anyone could go as far as to have a larger 1 TB external hard drive to store ALL of the information you need to socket away.

Back-Up Windows

Another way could be doing a backup in windows. You do this by selecting the Start button, then Control Panel System and Maintenance > Backup and Restore.

Do one of the following:

  • If you have never used Windows for Backup before, or you upgraded the version of Windows, select Set up backup, and then follow the steps in the wizard.
  • You could have created a backup before. If so you can wait for your regularly scheduled backup to occur, or you can manually create a new backup by selecting Back up now.
  • Finally, If you’ve created a backup before, but want to make a new one; full backup rather than updating the old one. Select Create newfull backup, and then follow the steps in the wizard.

Restore Point

The final way to back up any files would be to create a restore point. You can use a restore point to reclaim a computer’s files to an earlier point in time. 

These are automatically created each week by System Restore; when the PC detects a change, like when installing a new application or driver. 

Here’s how to create a restore point.

  1. Right-click the Start button, then select Control Panel > System and Maintenance > System.
  2. In the left pane, select System protection.
  3. Select the System Protection tab, and then select Create.
  4. In the System Protection dialog box, type a description, and then select Create.

Another way to set Restore Point

  1. Go to the Start button and right-click, then select Control Panel > System and Maintenance > Backup and Restore.
  2. You can do one of these to restore:
  • To restore your files, choose to Restore my files
  • To restore the files of all users, choose to Restore all users’ files

No matter what way you choose to back up the files, either option is perfectly fine. Now let’s move on to removing the CPU.

If hair is still attached to your head please continue.

Step 4: Preparing To Remove The Old Power Supply

Power down your PC, remove all the power and data cables, and then move it to your flat-work area. You’ll want to remove any access panels from the case (on some PCs, you have to remove the whole case as one piece). 

removing panels to remove power supply
Image Credit: technewsforyou

On a standard ATX case, these are on the right and left sides, held in place with screws on the back of the computer. Remove these screws (two or three on a side), then pull back the access panels and set them aside.

If you use a small form factor or other non-standard cases, consult the manual. Remove as much of the exterior panels as you can to give yourself maximum access to the interior: you’ll need to unplug power cables from multiple components.

Before You Remove Power Supply

Now, identify all of the components plugged into your power supply. On a standard PC build, this will be:

  • Motherboard: long 20 or 24 pin plug.
  • CPU (on the motherboard): 4 or 8 pin plug, near the top of the motherboard. You may need to remove the CPU cooler to see this if it’s an oversized cooler.
  • Storage drives: Hard drives and solid-state drives, usually plugged in with a standard SATA cable. Multiple drives may be connected to one cable.
  • Optical drives: Also use a standard SATA cable.
  • Graphics cards: Larger, more powerful discrete cards draw power directly from the power supply, even though they’re plugged into the motherboard. 6 pin and 8 pin rails are common, with some high-end cards needing multiple rails.
  • Case fans and radiators: When not plugged into the motherboard or case itself, these fans can draw power from accessory rails using small 4 pin connections

Hopefully, no one is lost and we just keep swimming, swimming, swimming!

Come Prepared

Check from both sides of your PC and multiple angles: excess lengths of power and data cables are often stored behind the metal motherboard mounting tray.

When you’ve identified which components are plugged into your power supply, unplug them one by one. Some may be held in place with plastic tabs, but you shouldn’t need to use anything except your fingers to unplug them. 

If you have to remove anything to get to these plugs, especially data cables, remember the original positions of those cables and restore them as you have access. Taking pictures as you go is a great idea.

One way to make things easier along with taking pictures is by labeling each cord. This is done by taking a small sticky note and putting it to the cord location either on the old PSU or the location from which it was plugged in. 

It allows you to keep track of how you unplugged the power supply so you can retrace your steps once you go to upgrade/install the new power supply.

Modular or Not?

modular and non modular power supply
Image Credit:

If your power supply is modular, you also can remove the power rails from the back of the power supply housing. Carefully pull them free of the computer case itself and set them aside. 

picture of modular power supply and not modular

If your power supply isn’t modular, simply pull all the power rails to the most accessible open space and make sure they’re free of entanglements with anything else in the case.

To know if your power supply is modular is based on the cords that attach to it. If your power supply is modular this means some of the cables can be removed and stashed away if you don’t need them. 

Non-modular is the complete opposite as no cables can be removed from the power supply. Fully modular indicates that all of the cables can be removed.

Removing Power Supply

Now turn your attention to the back of the PC. The power supply is held in place with three to five screws that are accessible from the outside of the PC case. 

Remove them and set them aside. Some case designs differ; if you see more screws in non-standard locations on the power supply, remove them too.

With all the cables unplugged and the screws that secure the PSU removed, you can now pull the power supply free of the case.

Depending on where the power supply is placed (top or bottom of the case) and what other components are nearby, pulling it out of the case might be easy or might be challenging. 

If it’s near the top of the case and it’s crowded by an oversized CPU cooler, for example, you might end up having to remove that cooler so you can get the power supply out.

Just make sure to be gentle with the computer as you don’t want to go banging the motherboard. I don’t have to tell you how painful that would be. 

Once you have safely removed the power supply and everything you marked to not lose track of any screws or cords, its time to install the new power supply.

More instructions on the ever-growing to-do list.

Step 5: Installing New Power Supply 

Reverse the Process

Now, we’re going to reverse the process and upgrade/install the new power supply. Place the new power supply in position on your PC. If it’s modular, don’t plug anything into it. If it isn’t modular, simply trail the power cables outside of the PC for easy access. 

Just double-check if it is non- modular. The cords make their way to the proper resting position before plugging anything in. It will save you some time when we start to retrace our steps.

Plugging everything back into the new power supply can be annoying if you don’t keep track of those cords.

Exhaust Fan

You’ll want to position the exhaust fan on the top or bottom of the power supply so that it’s facing away from the motherboard and the other internal components. 

So if the power supply is mounted at the top of the case, point the exhaust fan up. If it’s bottom-mounted, point it down. If the exhaust fan blows out the back of the case, it doesn’t matter. Just make sure it’s not facing your hardware!

Secure the power supply to the rear of the PC case with the retention screws, screwing from the outside of the case into the metal housing of the power supply. 

Use the screws from the previous power supply if you’re replacing it, otherwise, the screws should have come with either your PC case or the power supply itself. 

If the screws are old, stripped, or you are missing one or two of them I would use the new ones. Having more of them is good, especially if you lose them down the road.

When the power supply is fixed in place, it’s time to plug in all those cables.

If your power supply is modular, plug the cables into their sockets on the back of the supply itself. 

Now plug the opposite end of the rails into their corresponding components.

Remember those markings you made earlier? Just follows those backward from how many you made. 30 markings?! Are we repairing a car?!

Plugging In Your Hardware

So let’s begin by listing off each part so you don’t lose track of them:

  • motherboard
  • motherboard-CPU
  • storage drives
  • disc drives
  • GPU (if you are using one), and case fans or radiators

You should be able to plug everything in without any further tools. If something isn’t plugging in all the way, check the orientation of the plug; all of the multi-pin cables should only be able to fit one way. 

Try not to force the plug as it could bend the pins and that’s a big no-no. Just unplug it and re-plug it in to make double sure its plugged in properly.

As you are plugging in components, be wary of where you run the power cables. 

The inside of your PC doesn’t have to look like a showroom, but you should make sure that power and data cables don’t trail near cooling fans: they can drag and tangle. 

Even if they’re only touching slightly, they’ll make an annoying noise once your PC is running and potentially strip the protective casing.

Now keep going forward and progress onward!

Step 6: Double Check Everything is Plugged into the Power Supply

Keeping cables as tidy as you can. It not only looks better, but it also helps promote good airflow inside your case and makes components easier for you to get to in the future. 

Planning is key here to increase the longevity of the parts by keeping them cool. This is the part where it is needed to double-check and troubleshoot as required. Sometimes we can miss a cord or not fully plug it in all the way. 

As you are going through this process to upgrade/install a power supply, ALWAYS make sure to fully shut down the computer before tampering with the inside and unplugging the power supply.

It can become a lengthy process but you don’t want something to be ruined just because you skipped a step!

The Final Test

Once you are sure everything’s plugged in, you might want to move your PC back to its normal position with your mouse, keyboard, and monitor before closing up. 

Be careful not to touch any of the interior components while it’s running.

Plug everything in and power it up, just to make sure it’s booting correctly. 

If not, then go back and check your connections again to make sure you haven’t missed a power plug or accidentally removed a data cable. 

Oh, and check the switch on the back of the power supply to make sure it’s in the “ON” position. I always forget this one! 

If everything looks good, then unplug the external cables. Follow up by closing up the access panels, and screw them into place to get your computer ready for normal operation. Then place it back in its usual spot, and enjoy your newly upgraded power supply!