The power supply unit (PSU) is a vital component in any desktop computer. It provides electricity to the motherboard, processor, graphics card, storage drives and cooling systems. If your PC is shutting down unexpectedly, refusing to power on or showing signs of instability, the power supply could be the cause.
In this article you will learn how to check your PC power supply, understand its specifications and identify whether it is performing as it should.
Why Check the Power Supply
A faulty or underpowered PSU can cause all kinds of issues. These include random shutdowns, failure to boot, overheating or even damage to other components. If you are upgrading your PC, you will also need to check whether your current PSU has enough wattage and the right connectors to support new hardware like a graphics card or CPU.
Knowing your power supply’s make and model can also help you assess quality and determine how long it is likely to last.
Finding Out What Power Supply You Have
Unfortunately, most software tools cannot identify your power supply through Windows. Unlike other components such as the CPU or RAM, the PSU is not connected directly to the system in a way that allows it to be recognised by the operating system.
To find out what power supply you have, you will usually need to open your computer case and look at the unit itself.
How to Check the PSU Label
First, shut down your PC completely and unplug it from the mains. Press the power button once to discharge any leftover electricity. Then remove the side panel of your desktop case. The power supply is normally located at the bottom or top rear corner of the case.
You should see a label on one side of the PSU showing the brand, model number, wattage and electrical specifications. Look for information such as:
Wattage: This is the total power output, for example 500W or 750W
Efficiency rating: This may be labelled as 80 Plus Bronze, Silver, Gold or higher
Rails and amperage: These details show how power is distributed across components
Make a note of the brand and model so you can look up more details online if needed.
How to Check If the PSU Is Working Properly
If your PC is experiencing power-related issues, you can test the PSU in a few ways.
Using a multimeter
For advanced users, a digital multimeter can be used to check the voltage output of the PSU’s connectors. This test should be done with great care and only if you are comfortable working around electricity. You will need to test the 24-pin motherboard connector and any other relevant cables while the system is powered on.
Using a power supply tester
A power supply tester is a safer tool designed specifically for checking PSU health. You plug the PSU cables into the tester which then displays voltage readings and flags any irregularities. This method is ideal for home users who want to avoid risky multimeter testing.
Using another known working PSU
If you suspect your current power supply is failing, you can try replacing it with another unit to see if the issue is resolved. This can confirm whether the PSU was at fault, especially in cases where the PC will not power on.
Signs of a Failing Power Supply
Be on the lookout for warning signs such as:
- Random restarts or shutdowns
- Burning smells or electrical noise
- Failure to power on after pressing the button
- System instability under load
If your power supply is more than five years old and showing any of these symptoms, it may be time to replace it.
Matching Power Supply to PC Requirements
Before upgrading your PC or replacing a faulty PSU, make sure the new power supply matches your system’s power demands. You can use online PSU calculators to estimate your total wattage needs based on your components. Always choose a unit that offers a little more power than your system requires, and look for recognised brands with solid efficiency ratings.
A good power supply should also have the correct connectors for your components including 24-pin for the motherboard, 8-pin for the CPU and PCIe connectors for a GPU if needed.
Final Thoughts
Checking your PC power supply involves opening your case and inspecting the label for key information. While not as easy to identify as other components, understanding your PSU is essential for safe operation, troubleshooting and future upgrades. If your system is behaving erratically or you are planning to install more powerful hardware, knowing your power supply’s capability is crucial. Always handle it with care and seek professional advice if you are unsure.