A power supply unit is one of the pivotal components of any PC, without which nothing works.
Knowing the exact specs of your PSU can help you determine if your system has the best configuration for your computing or gaming purposes.
However, the very nature of a PSU makes it difficult to find a straightforward way to check its specs.
This article explores different ways to see what PSU you have.
How To Find Out What Power Supply You Have (3 Ways)
1. Check The PSU Physically
If you have assembled your PC and it’s not a pre-built computer, you should know the PSU’s specs before.
If it’s a pre-built PC, though, you may not know what power supply you have.
Power supplies don’t communicate with motherboards because their only job is to supply power to the PC components.
There’s no way to know what PSU you have through your computer interface.
The easiest way to know your power supply is by checking it physically.
Every PC provides information about the PSU inside the case at different locations, depending on the manufacturer.
You will need to open the computer case’s side panel and find the PSU with a label or sticker on the side or at the top that lists all the information about the PSU.
Depending on the model and manufacturer, the power supply may be mounted in another case inside the computer, which you have to unscrew.
In that case, you have to open the PSU shrouding box.
Here’s how to do it:
First, power off the computer and unplug all the wires, including the power cord and other peripherals.
You should either unclip or unscrew the side panel to open the case, depending on the make and manufacturer.
The power supply is easy to find, usually near the power cord’s port.
All power supplies must have this sticker to show their specs, so if you can’t see it, it has to be on the side of the PSU that’s not visible.
If there’s no sticker or label on any side, it’s not a reliable make because the Underwriters Laboratories require every manufacturer to provide this information.
Therefore, you may want to change your power supply before it damages your PC.
2. Online Search
This method is particularly helpful if you have a pre-built PC, but you don’t want to open your case.
You can refer to the manufacturer’s website, enter the model number of your PC, and look for the PSU specs provided for that model number.
However, since manufacturers may change the PSU specs and features in some newer offerings of the same model, the safest bet is to open the case and check it physically.
You may not find the information on some manufacturers’ official websites, though, because not all of them provide such information.
It also helps to search your PC’s make and model number on Google and look for the power supply’s specs on trusted websites.
There are online forums with dedicated and knowledgeable members who can help you find out what PSU you have.
3. User Manual
If you have a pre-built PC, you can refer to the user manual and find out what power supply you have.
The manufacturer lists all the specs you need to know.
If it doesn’t, you may find the model number of the PSU and use it to search online and look for the details.
What Information Is On PSU Label?
Regardless of the method to open the case, you should find the following information:
1. Name And Model Number
The name and model number of the PSU are typically in large, bold letters on top of all other information.
Some manufacturers include the wattage of the PSU inside the name and model number.
Knowing this name allows you to find out more information by Googling the name and going to the manufacturer’s website.
That’s particularly helpful when you don’t find any information on the label other than the name.
As mentioned, you can find the wattage of your PSU next to its name and model number in most cases.
Otherwise, it’s written in bold fonts like 200W or 500W.
The power supply’s wattage indicates its output or ability to provide power.
The higher the wattage, the more power it can provide, and the more powerful components you can use.
The voltage can be in two forms: input and output.
The input voltage means how much power the PSU needs to get from the power outlet.
This input mainly depends on your region because different countries have different voltage inputs for their electronic devices.
For example, in North America, this number is 110V, and in Europe, it’s 200–240V.
Some power supplies have a flexible input voltage ranging from 110–220V.
They can adapt to the input through their built-in auto-switching mechanism.
If it doesn’t come with this mechanism, it should come with a physical switch to adjust the input.
The output voltage is another spec you will see under voltage.
There’s a wide range of standard output voltages that span +3.3V, 5.5V, 12V, and 5VSB (standby voltage).
As the name suggests, the standby voltage powers some components such as the mouse, the BIOS, memory, keyboard, and LAN, supporting Power-on features when the PC is in standby mode.
There are also negative output voltages, ranging from 12V to -5V, and zero.
You could also find these voltages represented in Rails.
The output voltage involves the voltage that goes into each component, which can be different for each.
The sum of these voltage requirements determines the system’s total power need.
4. Maximum Power
The maximum power refers to the highest power, shown in watts, that a single rail can draw.
Sometimes, it’s the combined power of two or more rails and is calculated as the product of voltage multiplied by current.
Knowing this maximum power lets you know how much power you can draw for each component.
That’s particularly important when you want to build your PC and make sure each component gets enough power.
5. Max Current
The current, or in some PSUs, the max load, is the highest amount of current each rail can offer.
It’s shown under each rail and shows that it’s the maximum current it can provide for different components and can’t go over that.
Anything higher, the PSU will fail, or the computer will shut down.
6. Total Power
Measured in watts, the total power of a PSU shows the power of all rails combined.
It’s the same as the number indicated for wattage since they’re the same thing.
If they’re not the same, it shows that the manufacturer has chosen to indicate the highest rail’s total power, which is the 12V rail.
That’s because it’s the most significant rail in the PSU and can power most of the computer’s main components.
7. 80 Plus Rating
PSU manufacturers receive an 80 Plus rating that shows how reliable they are.
These ratings include Titanium, Platinum, Gold, Silver, Bronze, and 80+.
It rates them on efficiency, stability, safety, and components used.
The more efficient a PSU is, the lower it’s electricity consumption and the higher the output/input ratio are.
If your PSU has a high stability rating, it means high temperatures or loads don’t affect its performance.
Some low-stability PSUs may shut down or burn under such circumstances.
If a power supply unit isn’t safe, it can put all other components that get power from it in danger, too.
It should have some safety mechanisms, such as Over-Voltage Protector (OVP) and Under Voltage protector (UVP).
Finally, the 80 Plus rating shows how good in quality the PSU’s components are.
Naturally, these components affect the performance of the PSU, making it reliable.
Why Do You Need To Know What Power Supply You Have?
The power supply plays a crucial role in your computer and can affect its overall performance and how each component works.
That’s because it sends power to all components based on their power requirements.
It also changes the AC voltage into a low voltage DC that computer parts can use.
If you’re happy with your current PC and don’t want to make any changes, or if you’re not that technologically savvy, you may never need to know your power supply’s features.
However, if you want to upgrade your components or overclock your system, knowing what power supply you have is necessary.
Suppose you want to turn your PC into a gaming rig, getting a stronger GPU.
In that case, you need to know if your power supply can give the GPU enough power to run efficiently and at full capacity.
If you don’t use a suitable PSU, you could damage the components by not giving them enough power.
The most important factor is the PSU’s wattage.
The power requirements of all PC components should be lower than the total wattage of the PSU.
Otherwise, your computer will shut down, or the PSU will fail.
Knowing the limits of your PSU enables you to choose the best components you can.
If you’re in the market for upgrades, you can also look for a stronger power supply compatible with new components.
If you want to upgrade, you need to know your power supply’s maximum load.
What about the components?
How can you make sure the new components don’t overload the PSU and cause it to burn?
As a general rule of thumb, after calculating your total power demand, go about 150W above that to make sure every component receives enough power.
If you want to buy a power supply, however, it can be challenging to figure out what size you need.
You can use different methods to figure out this number:
Your computer’s PSU powers the following components:
- Optical drive
- Fans and peripherals (although most of them have their own power cables or draw power using USB connections)
- And just about anything inside the chassis.
You should know the combined voltage of these components.
Then use the following equation to get the required wattage for the PSU:
Power = Amps x Voltage
That’s a simple solution, but you should know the voltage and amps of all components.
If you want a more straightforward process, try the below solution.
Power Supply Calculator
There’s a wide range of online tools that take the guesswork out of the process and help you determine how big a power supply you need.
You simply enter the components of your PC or the ones you want to buy, and it will calculate how much power they require.
Some of these tools even tell you if your components are compatible or if you’re going with the wrong combination.
How To Choose The Best PSU
Now that you know what size PSU you need, you should consider some other features that make a good PSU.
1. Custom Vs. Standard PSUs
When you’re in the market for a power supply, you may hear two names frequently: custom and standard PSUs.
Standard PSUs are gaming-specific PSUs that manufacturers like Cooler Master and Corsair build.
These power supplies are heavy and feature high-quality components and cables covered in black exteriors.
Custom power supplies are used in pre-built PCs and feature lower-quality and lighter materials, especially aluminum exteriors.
You can locate their fans on the back of the PSU, unlike standard PSU, which have their fans on their top or bottom.
They cost less than standard PSUs and are made by less reputable brands like Intex and Zebronics.
While standard PSUs have lots of cables and sleeves, standard PSUs feature fewer cables and no sleeves.
If you want a strong power supply for your gaming rig, it’s better to go for a standard power supply made by a famous brand.
Another thing you should consider when buying a PSU is size.
Not every PSU can fit into your computer case since there are different form factors.
Therefore, you should consider the form factor before choosing a power supply unit.
If you’re upgrading your PSU, take the old unit to the store or measure its dimensions to ensure it fits.
If you’re building your system from scratch, decide where the PSU should go and measure the dimensions and compare it to the clearance inside the case to find the right fit for it.
A modular PSU enables you to attach the cables based on your needs and system requirements.
Traditional, non-modular PSUs don’t have this feature, and their cables are permanently attached to them.
There are also semi-modular PSUs with both permanently attached and detachable cables.
The biggest advantage of modular PSUs is that you have more control over what to include and ignore in your connections.
This way, you can reduce clutter inside the case and improve airflow and aesthetics, especially in transparent cases.
However, if you use a modular PSU, you have to use the proprietary cables provided by the manufacturer, and you can’t use aftermarket cables if you ever need to.
Even if you use the cables from the same manufacturer, they may not be compatible, so you must be very aware of any new cables you purchase for your modular PSU.
How To Make Sure The PSU Is Failing
Sometimes you may need to change your PSU because it’s going bad, not because you want an upgrade.
A failing PSU can be hard to pin down because its symptoms may be signs of other system issues.
However, some signs are more telling than others, including:
- The computer crashes randomly.
- The system won’t start, although the fans are spinning.
- You experience blue screen crashes for no apparent reason and randomly.
- Different PC components seem to fail repeatedly.
- You hear extra, unusual noise from the PC.
To make sure these symptoms are the signs of a failing PSU and not another problem, you need to test it.
The best way to make sure your PSU is going bad is to replace it with another unit that you know is working properly.
When you perform this test, make sure to follow safety precautions because PSUs contain dangerous amounts of electricity and can lead to disastrous accidents if you don’t know how to handle them carefully.
Unplug your PSU from the motherboard and GPU, connect the new PSU, and plug it into the wall outlet.
Turn on the PC, and if it works normally, the PSU is at fault.
You could also perform the paper clip test, demonstrated in this video: