The PSU is the most underrated and often overlooked component in a desktop computer. It is typically the last piece of equipment that someone upgrading their system will think about, yet it is probably the most important.
The power supply unit provides power to all of the other components in your system. If it is not powerful enough, or cannot provide enough current, then your system will not be able to function correctly. In extreme cases, a weak PSU can cause damage to your other components. For this reason, it is essential to know what power supply you have in your system and make sure that it is up to the task of powering your system.
In this article will discuss how to find out what power supply you have in your system and the critical metrics you should know.
How to find out what power supply you have? [3 easy ways]
Unfortunately, you can’t find out what power supply you have through Windows’ built-in tools. Power supplies send only power to your PC and no more information. However, there are three ways to find out what power supply you have in your system. The easiest way is to look at the label on the PSU itself, so let’s start there.
1. Physically Inspect The PSU
The first and easiest way to find out your PC’s power supply specifications is to check it physically. Every PSU has a label that lists its most important specs. But to do so, you’ll need to open up your computer case. I know that many of you are not so keen on opening up your computer case, but it is not difficult, and it only takes a few minutes. So let’s see how to do it in simple steps.
How To Locate The PSU?
- Unplug your computer from the wall outlet and remove all cables from the back of the system.
- Open the side panel of your computer case.
- Locate the PSU. It is typically mounted at the top or bottom back of the case.
- Carefully remove the PSU from its mount. You will need to unscrew a few screws, so you should have a screwdriver handy.
- With the PSU in your hand, locate the label with all the specifications. This label should be easy to find as it is usually located on the side of the PSU.
Great, now you can read the label on your PSU and find all the critical specs we will discuss later. But what are the specs that you should be looking for, and what do they mean?
What Information Is On The PSU Label, And Why Is It Important?
Let’s see what information is typically found on a PSU label and why it is important.
Manufacturer / Model
Usually, the first thing you will notice on the label is the manufacturer and power supply’s model. This information is essential because if you want to use a warranty or check for compatibility issues, you will need to know the exact model of your PSU. Also, if you want to read more about your PSU, you can google the model and find more information about it.
The power supply wattage is probably the most important number on the label. It is the maximum power that the PSU can deliver. It is essential to know because you need to make sure that your PSU can handle all of the components in your system. The power supply’s wattage is measured in watts (W), and the higher the number, the more powerful the PSU.
AC input is the voltage your PSU requires from the wall outlet and is measured in Volts (V). The AC voltage ranges from 100V to 240V. In USA and Canada, the standard is 120V, while in Europe and most of Asia is 200V – 240V. Modern PSUs have an auto-sensing feature that allows them to work with both 120V and 240V.
DC output is the voltage that the PSU delivers to your components and is also measured in Volts (V). The most common DC output voltages are +3.3V, +5V, and +12V.
The max load is the maximum current the PSU can deliver to each voltage rail and is measured in Amps (A). The +3.3V, +5V, and +12V rails have a maximum power rating of 20A, 30A, and 36A.
Maximum Combined Wattage
The maximum combined wattage is the maximum power that the PSU can deliver to all of the voltage rails combined and is measured in watts (W). To calculate the maximum combined PSU wattage, you need to add the maximum power of all the voltage rails. For example, if the +3.3V rail has a max load of 20A and the +5V rail has a max load of 30A, the maximum combined wattage would be 3.3V x 20A + 5V x 30A = 66W + 150W = 216W.
The total power is the maximum power that the PSU can deliver and is measured in watts (W).
The total power is important because it tells you the maximum power your PSU can deliver. This number should be higher than the maximum combined wattage.
80 plus rating is a certification that tells you how energy efficient a PSU is. The 80-plus rating has three levels: Bronze, Silver, and Gold.
A Bronze-rated PSU is at least 82% efficient, a Silver-rated PSU is at least 85% efficient, and a Gold-rated PSU is at least 87% efficient.
The 80-plus rating is significant because it tells you how energy efficient your PSU is. Higher efficiency means less heat and a longer lifespan.
2. Search Online
The second way of finding out what PC power supply you have is to search online for the model number of your PSU. Once you know the model number, you can go to the manufacturer’s website and find your PSU tech specs.
If you have a pre-built PC, you can also go to the manufacturer’s website, look for your model number, and find your PSU specs.
If you have built your PC, you should look at the box of your PSU and find the model number. Once you know the model number, you can go to the manufacturer’s website and find your PSU specs.
3. Look In The Manual
The last way of finding out what power supply you have is to look in the manual.
If you have bought a pre-built PC, find the manual that came with your PC. In the manual, there should be a section that lists all of the specs for your PC, including the PSU.
Related Article: How To Connect Power Supply To Motherboard In Easy Steps
Why is it important to know what power supply you have?
Knowing your power supply is one of the most important things when building or buying a PC.
The PSU is the most critical component in your PC because it delivers power to all your other components. If you have a low-quality or incompatible PSU, it can cause instability, crashes, and even damage to your components. A good PSU should be able to deliver enough power to your components and be compatible with your motherboard.
If your PSU cannot deliver enough power to your components, it can cause your PC to crash or freeze.
To avoid these problems, it is essential to know what power supply you have and the power requirements of your components. Knowing these things will help you choose a compatible and high-quality PSU for your PC.
How To Calculate The Power Requirements Of Your Components?
- The first step is to make a complete list of all your components. This list should include everything from your CPU to your case fans.
- Once you have a complete list of your components, you need to find the voltage and Amps of each component. The voltage and Amps can be found in the specs of your components or on the manufacturer’s website.
- After you have gathered all of the necessary information, you can start calculating how much power your components need.
- To calculate the power requirements of your components, you need to multiply the voltage by the Amps. You can use the following formula: P( Watts ) = V( Volts ) x I( Amps ). For example, if your CPU requires 1.2 Volts and uses 20 Amps, the power requirement of your CPU would be 24 Watts.
- Use this formula to calculate the power requirements of all your components. Once you have calculated the power requirements of all your components, you need to add them all up.
- The total sum is the minimum power requirement of your PC.
- Add 20% to the total sum if you want to be safe. For example, if the total power requirement of your components is 100 Watts, you should get a PSU that can deliver at least 120 Watts.
I know at this point, many of you will be wondering if there is an easier way to calculate the power requirements of your components. And the answer is yes; there are a few online calculators you can use.
Free Power Supply Calculators
As I already mentioned, there are a few free power supply calculators that you can use to calculate the power requirements of your components.
These calculators are straightforward to use and only require you to input the information of your components.
After you have inputted the information about your components, the calculator will do all the work for you and give you the minimum power requirement of your PC.
Here are a few free power supply calculators that you can use:
How to Choose a Power Supply
Now that you know how to calculate the power requirements of your components and what power supply you have, it is time to choose a new power supply for your PC.
Standard vs Custom Power Supply Units
The first thing you need to do is decide if you want a standard or custom PSU. Standard PSUs are usually cheaper and easier to install than custom PSUs. They are also more widely available and come in a variety of shapes and sizes.
Custom power supplies are more expensive but offer better performance and are more customizable. Choosing a custom PSU of a brand like Corsair or Cooler Master will usually give you the best results.
This doesn’t mean that all standard PSUs are bad; there are still a few good standard PSUs on the market. But, if you can afford it, I would recommend going with a custom PSU.
The next thing to consider is the form factor of your PSU. Just like motherboards and cases, PSUs come in different form factors.
The most common PSU form factors are ATX, SFX-L, and SFX. The ATX form factor is the most common and is compatible with most cases. If you are building a gaming rig, I recommend going with an ATX PSU.
The SFX-L form factor is less common but is still compatible with most cases. The SFX-L form factor is between the size of the ATX and SFX form factors. If you are looking for a smaller PSU, the SFX-L form factor might be a good option.
The SFX form factor is the smallest PSU form factor and is only compatible with cases that support the SFX form factor. If you are looking for the smallest possible PSU, the SFX form factor is your best option.
Modular vs Non-Modular Power Supplies
Another thing to consider when choosing a PSU is whether you want a modular or non-modular PSU. The difference between modular and non-modular PSUs is that they have detachable cables, while non-modular PSUs have all their cables permanently attached.
Modular PSUs are more expensive but offer a few benefits over non-modular PSUs. The main advantage of modular PSUs is that they provide better cable management. This is because you can detach the cables you don’t need, giving you more options for routing your cables.
I recommend buying a modular PSU only if you are an experienced PC builder. If you are a beginner, I recommend sticking with a standard non-modular PSU.
Power Supply FAQs
What PSU Do I Need?
The PSU that you need depends on the power requirements of your PC components. You can use a free online power supply calculator to calculate the power requirements of your components. This way, you can be sure that you are choosing a PSU that can handle the power requirements of your components.
How To Tell If Your Power Supply Is Bad?
There are a few signs that your power supply is bad. The most common sign is that your PC will randomly shut off or restart. Another sign is that your PC will not turn on at all. If you notice any of these signs, I would recommend trying to find out if your power supply is bad. The easiest way is to use another PSU to test your system.
How Often Should I Replace My Power Supply?
As long as your power supply unit (PSU) is working and isn’t exhibiting any strange behavior, you should not need to replace it. Power supply units have a long lifespan and typically outlast multiple motherboard, CPU, and memory upgrades. However, if you’re upgrading your system’s components or building a new system from scratch, you should consider upgrading your power supply unit.
Now you know your power supply, how to read the specs, and what they mean. This will help you understand your components’ power requirements and how to choose the right PSU for your needs. I hope this guide was helpful and that you now understand power supplies better. If you have any questions or comments, feel free to leave them below. Thanks for reading!
Nick Ryley is a computer architect and the owner of The Pc Geekz.
His love for playing games got him interested in computers in the first place. He wanted to be able to build a gaming PC that could run all the latest games at max settings, and this has him pursuing a major in computer architecture!
He started this blog to help people out and answer some of the most common questions about computer building