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How to Know If Your Computer Power Supply (PSU) Is Failing

How to tell if your PSU is failing

How to tell if your PSU is failing

Power Supplies Fail Sooner or Later

Much like hard drives in computers, all power supply units (or PSUs for short) eventually fail. Like hard drives, it isn't a matter of if—it is a matter of when and why. In this article, you will learn how they fail, what some of the common symptoms are, and how to diagnose the problem.

An Apple Laptop PSU Might Look Like This

An Apple Laptop PSU Might Look Like This

So, What Is a Power Supply Unit, Anyway?

Inside a computer, a PSU is the device that converts alternate electricity (the electricity from your outlet, normally 110V) to direct current to the components inside the case. Looking from the outside, it's the three-prong plug that plugs into your socket. Laptops' are much the same, except they're external: A block and cord that attaches to the back and plugs into the wall.

Every power supply is different. Some (typically for laptops) may have a low output of 65 watts, while others might output 1,000 watts or more. Some may only have 10 amps, while others output 65 amps.

When the PSU is no longer delivering the power your computer needs, things start getting wonky: See below for the signs.

A PC Laptop PSU Might Look Like This

A PC Laptop PSU Might Look Like This

Symptoms of a Failing Power Supply

More often than not, you just don't get any warning that the PSU is going to quit on you. However, sometimes it may do one (or more) of the following before it kicks the bucket:

  • Strange noises may emit from the back of the computer case where the cord is located.
  • When the computer is turned on, nothing happens. Sometimes this may coincide with a flashing light on the front of the computer or an indicator on the back of the PSU (if equipped).
  • The computer turns on for a couple of seconds and then turns right back off. While this can be a power supply issue, it may also indicate motherboard failures.
  • The computer is on for a while, but maybe while you're playing a game or using another application, it just randomly turns off without warning. It might also display a blue screen of death.

When gaming is involved, one must realize that video cards these days require a lot of power and amperes to run correctly. When purchasing a PSU, be sure you have the wattage and amps needed for the equipment inside of your computer, especially the video cards.

The Blue Screen of Death May Indicate a Failing PSU

The Blue Screen of Death May Indicate a Failing PSU

So, Why Do PSUs Fail?

Power supplies just fail. Failures can be instigated by something you've done, but sometimes, the unit simply gives up. Below is a list of common factors that send a unit to its grave.

  • Age: Most warranties last from 5-10 years, but that's no guarantee. Its life also depends on how often you use your computer.
  • Electric Interference (lightning, power spikes, etc.).
  • Dirt/Foreign Substance (cigarette smoke, house dust, etc.).
  • Brown-Outs: Intentional or unintentional drops in voltage. These load reductions are sometimes used in emergencies, like during a heatwave when everyone is using their A/C.
  • Overheating and/or Ventilation Failures.

The most common reasons are overheating and lightning. However, if you are a cigarette smoker or the computer is in a dusty environment, rest assured you will be replacing your PSU sooner rather than later.

A Desktop Computer PSU Might Look Like This

A Desktop Computer PSU Might Look Like This

Can Anything Be Done to Prolong the Life of a PSU?

Yes, there are a few things that will help you get the most out of a power supply. You should be able to extend its life beyond the manufacturer's warranty. Just remember that it isn't going to last forever.

  • Make sure you are not maxing out the wattage with the additional equipment you install. The power supply should exceed your system's requirements by a minimum of 20%.
  • Don't cheap out and purchase a junky unit. A nice one will cost a little more but will go a long way.
  • Keep it as dust-free as possible.
  • Keep it, along with the rest of the computer, under 80 degrees.

Keeping the air quality clean may be difficult in some scenarios, so getting an air filter would be useful. Occasionally cleaning the system out will also prolong its life. The computer needs to breathe, or it will overheat and die.

True Story

I was at a client's house to have a look at her computer. She said it wouldn't start. I had already assumed the PSU was bad, but I didn't expect to find even more when I arrived. It turned out the power supply had zapped every single component in the computer except a single DVD-ROM drive at the very top of the case. None of the components (motherboard, CPU, hard drive, etc.) had any signs of a surge, such as burnt chips or even the smell of them being burnt.

In the end, the only other devices that powered up with the computer with a working PSU were the system case fans. I wasn't there when the power supply blew, but I would have to imagine that it released some sort of electromagnetic pulse through the whole system.

This was a weird case and an educated guess as to what happened; however, there really isn't any other explanation. The hard drive wouldn't even spin. Only the devices that produce a natural electromagnetic current (fans) and the DVD drive (which was higher than the power supply) survived.

Lesson to be learned: Back up your data!

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2009 Ryan Hutzel

Thanks for Stopping By.....

Ryan Hutzel (author) from Greencaslte, PA on June 21, 2020:

A hard drive beginning to fail can cause these same issues.

Sasha Puksich on June 21, 2020:

I am having excatly the same problem as @Atrix224. What's even weirder, my hackintosh (macOS Catalina) is working with no problem, on the same system. As soon as I try to boot into my dual boot Windows 10 disk, or I try to boot with my windows 10 install USB stick, system sooner or later restarts with no blue screen or warning.


Atrix224 problem:

Can a bad psu be the cause of restart looping? Even when trying to use a flash drive it still restarts before I even make it to a win 10 recovery. I've already tested ram GPU and my drives and still not change. I can still enter the bios just done and can stay in there as long as a want so I can't figure out if my issue is from psu or maybe motherboad.


Ryan Hutzel (author) from Greencaslte, PA on May 05, 2019:

This is likely a bad PSU, they are not suppose to turn on without being told to by the motherboard or as you stated, jumping the connection with a paperclip.

Ryan Hutzel (author) from Greencaslte, PA on May 05, 2019:

What you are describing sounds more like a bad motherboard or chipset drivers need updated.

Atrix224 on April 25, 2019:

Can a bad psu be the cause of restart looping? Even when trying to use a flash drive it still restarts before I even make it to a win 10 recovery. I've already tested ram GPU and my drives and still not change. I can still enter the bios just done and can stay in there as long as a want so I can't figure out if my issue is from psu or maybe motherboad.

Nordog on April 06, 2019:

Just bought a new PSU and it jump starts itself without Motherboard or "paperclip"ir does this when Motherboard PSU cable is connected to PSU. Have a video with problem will link it. And then i got a replacement with the same problem,what's wrong with this PSU?

Ryan Hutzel (author) from Greencaslte, PA on March 20, 2019:

Inadequate amperage to any electronics can cause a brown out scenario. While not guaranteed that it caused damage, it is a possibility.

varun kuckian on March 18, 2019:

i just bought a used gtx 1050ti and used it for two days but the third day my pc sutomatically shut down ,now its not opening . later i realized my psu was very bad to run my specs so so i bought a new psu (vs450)..i would like to know in this complete situation is there a chance of my graphic card to get corrupted due to psu failure .since gtx 1050ti was very costly i am in a high tension that my psu did or didnt destroyed it please suggest me something

Gopal15216 on October 20, 2018:

my rig is fx 6300 raideon hd 7750 before it run good without any lag but when I upgrade to gtx 660 when play game all OK but after few days my smps dead it happen three times smps are clarian 550 watt circle 400 watt and unfortunately corsair vs 650 to I realise due to 600 va ups is the cause but when I replace ups to 1000 va nothing happen again one smps foxin 450 dead to I can't understand why this happen.

Ryan Hutzel (author) from Greencaslte, PA on August 29, 2018:

@Ospina01, I would lean more to the video card. Physically inspect the video card for bulging capacitors. 5 1/2yrs is a very long time for a PC these days.

Ospina01 on August 29, 2018:

If i may, im having a slightly same issue. I do CAD so i have a pretty beefed up system (back in the day) which is about 5 1/2 years old. When i boot it up everything loads (post), "window 7" appears and it pauses for about 10 seconds (its SSD) which it didn't use to do then the windows begin to flow in as it starts, it gets to that point and it flashes and i get the blue screen of death, says "attempt to reset the display driver and recover from timeout" then it reboots with options for "safe mode" i can load into safe mode but the screen has what looks like the matrix green pixels in all the gray to black areas but i can see everything in safe mode. Could you help me with am I looking at a new video card or a new power supply? Card (Nvidia GTX 480) because of the green pixels, power supply because of the SSD load time / age maybe the power band is just gone (CORSAIR AX1200 Watts) but it has enough to run in safe mode.... Help with any suggestions.

Ryan Hutzel (author) from Greencaslte, PA on August 12, 2018:

Mark, you seem to be describing a fan failure. May want to check all the fans to see any of them are seized, including the one inside the power supply.

MarkVince on August 11, 2018:

I played my computer last night, but before i open it, my psu is making a grinding sound.. I plugged it out and plugged it back in, then the sound was gone..

This morning i tried to power it on again and then made that noise again.. So i decided to clean it because i thought it was just a dust..

But when i plugged it in and press the power button, it still make that noise but this time i saw a spark inside my / mobo... My screen was on and it flashes my mobo but i unpluged it once i saw the spark inside and the it smells like burnt plastic..

Is my power supply the issue?

I dont think my mobo is the problem, i hope its not damaged,cuz of the burning smell :/

Ryan Hutzel (author) from Greencaslte, PA on August 10, 2018:

I am assuming the CPU is clear of dust and has adequate thermal compound to keep it cool. With that said, this sort of description without swapping out the power supply with a known good unit or testing it with a tester, it is too difficult to know the truth. If the system having all lights on, but nothing running indicates a memory, cpu, or video card failure typically.

mohammedmoha on August 09, 2018:

hi it may not be the same problem but during the last month I am getting black screens randomly but the pc itself is running. I have to manually shut down the pc for it to become usable again.

I did some tests on the CPU, the RAM and the SSD but cannot find anything useful. The intervals between the shut downs are not the same either. Sometimes it can happen multiple times in a single day and other times it can take more than a week for it to show the problem. The PSU is 750W.

Ryan Hutzel (author) from Greencaslte, PA on July 28, 2018:

Given the description, this type of question is not able to answered directly. The only thing I will say is that if the system now has water cooling, be sure that you have the sensor plugged into where the CPU fan would have been. Also, if the video fan is not cooling, all that you have described would happen, however I cannot conclusively say that it is this.

JayWestern on July 28, 2018:

Hi my PC has been failing for a while now. The CPU started overheating (its AMD) so I replaced the stock CPU fan with a water cooling system which seems to have dropped the temperature down to 40. however when I booted up my PC after the water cooling was installed the PC would turn on for a few seconds, and then the screen would go black and the GPU fan would stop spinning. I tried to boot it multiple times but had the same result. Then after leaving the PC alone for a few weeks I decided to give it a retry and it booted up. It seemed perfectly normal, but after a few minutes the screen went black and the GPU stopped spinning again. I don't believe its the power supply because its 550V and the GPU is low profile, but before I buy a new GPU I would like reassurance that that its not due to my power supply or any other component.

Ryan Hutzel (author) from Greencaslte, PA on July 16, 2018:

Your issue may not be the computer at all. Sounds like you may have a ground issue on the electric circuit. I would try a decent battery backup unit or get a electric filter in place of or along side of your surge protector. I am assuming this only if your computer runs normal when the air conditioner is off.

Devan Knisley on July 15, 2018:

I've been having issues with my pc when the air conditioning is on. My pc restarts and u get the America megatrends power surge detection screen. I then get brought to the BIOS. It then restarts and the process repeats itself. Now my pc tries to start but then shuts down and repeats the process. I've tried power surge protectors and protectors with batter backup but nothing has helped. I'm starting to think I need a new psu. Is it the problem?

Ryan Hutzel (author) from Greencaslte, PA on July 05, 2018:

You are describing a hard drive or motherboard. It doesn't matter how new or old components are if they are failing.

shawnbry on July 02, 2018:

My computer is usually fine, but occasionally won't launch windows. It either goes to bios, then nothing (screen turns off) or it endlessly tries to self diagnose and restart. The only old components on it are the motherboard and psu, everything else is new; usually disconnecting the dvd drive allows it to start. Could it be that the PSU is the real problem?

Ryan Hutzel (author) from Greencaslte, PA on June 22, 2018:

If your power supply is a stock power supply from a manufactured (not custom) computer, it is a high probability you have an underrated power supply. Kind of answered your own question, when the PC is demanding a full load, it shuts off. The only other thing that will cause a computer cut off power without a blue screen or freezing is overheating or bad CPU.

Jack Raspo on June 20, 2018:

Hey Ryan,

So I have been trying to figure out why my PC shuts off every time when its on a heavy load. When it shuts off I have to unplug the power cord. I had a gtx 660 so I upgraded to a 1060 6B just yesterday. But it still does the same thing. I even blew out the dust because I know it conducts electricity. Still doesn't work. How can I fix this?

Tharaqon on May 15, 2018:

Hello Ryan,

Thank you for the speedy response. I shall then probably continue with cashing in my carry-in warranty, in hopes that it does indeed fix the problem.

Thank you again.

Ryan Hutzel (author) from Greencaslte, PA on May 15, 2018:

Tharaqon, in short if the computer is just shutting off without warning, it is highly probable that the PSU is bad or inadequate for the setup (amps/wattage.) Also, bad capacitors can do what you are describing as well.

Tharaqon on May 15, 2018:


I have some issues with my desktop lately. When playing some games (not all), my computer sometimes randomly reboots itself. No BSOD. I have since disabled the windows option to automatically reboot upon failure, as a google search said that would then trigger the BSOD instead of just reboot (in hopes for an error code that could help in troubleshooting). This did not work, still just random reboots. (everything instantly turns off, black screen, and after a second or two system automatically turns on again).

Note that this is purely of the last few weeks; in the two years I have had this exact set-up I had no problems, only lately (since a month ish) I have had these random reboots. Most notably during Fortnite. During Kingdom Come Deliverance (a much more demanding game, as far as I know) has had no issues.

I checked temperatures and they are fine (under 60C on all components using speedfan). My current PSU does not have a 12V rail sensor, so I cannot readout the voltages to see if they drop just before the random reboots.


Intel i5-4460 CPU

MSI H97M-G43 motherboard


2x 8GB RAM

cooler master GM G750M PSU

Computer also runs an SSD, optical drive, HDD, wifi card

and 4-5 USB devices simultaneously (keyboard, mouse, headset charger, wireless Bluetooth headset connector, misc.)

So far my searches have found no cause, so I am starting to fear it is my PSU. It is nearly 2 years old now, so it would seem young to me. However I still have carry-in, so it would just be a hassle to replace if it is indeed failing.

Does anyone here have an idea as to what could be causing my issue?


Now that I come to think of it, I have lately replaced my SSD as my old one died after 6 years of loyal duty. It is my boot-disk SSD, 240 GB by Samsung


I did not notice the computer claiming only half of the RAM is available after the random reboots as Firehawk did two years ago. However, I did not inspect this aspect either.

ahmad abdulal on August 31, 2017:

I have just finished building my new pc and when i start it, everything goes on but i got nothing on the screen and all of the usb are not working. Can it be the psu?

I tried to run my pc without any memory ram and i got no led from the motherboard that shows it need ram.


Ryan Hutzel (author) from Greencaslte, PA on June 22, 2017:


It appears your fan speed is running slow, 2500 rpms is slow. 3-3500 is average. My thoughts would be to buy a better after market heatsink/fan that is rated for you CPU.

Will on June 22, 2017:

My computer is running at 70-80C idle on the CPU and Motherboard.

And baciscally everyone on Reddit recommended to re-apply my thermal paste, which I have done and there isn't any change in temperature. Please Help.

Ryan Hutzel (author) from Greencaslte, PA on May 26, 2017:

The loud pop is most often a capacitor blowing out. Capacitors are located on almost all circuit boards. Look generally on the motherboard, video card, and or psu. It could be a PSU issue, however not exclusively.

Brian on May 24, 2017:

Was playing a game on my PC when I heard a loud pop and now won't even turn on could this be a psu issue?

YOUDIEMOFO on September 04, 2016:

Electromagnetic Pulse went through the whole computer eh....?!?

Now I think I have heard it all....

Trollinjaflex on April 22, 2016:

What if my PC was making electric shocks ,does this mean my psu is failing

Firehawk4nzzz on November 19, 2015:

ryansccs...thank you, i am truly grateful, i was under the impression it was only using 50 watts, i don't even know why, but thats what i thought...thank you, sure this means I will need a new psu, but thanks to you i can at least identify the problem, really i can't thank you enough for responding so quickly...thank you!

Ryan Hutzel (author) from Greencaslte, PA on November 19, 2015:

@Firehawk4nzzz, The GTX 750 requires 400w minimum with 20amps on 12v rail for PSU. Get a new power supply, you are under wattage. At this point it is very possible you are simply "brownout" your system. To much amperage needed, not enough wattage either.

Firehawk4nzzz on November 19, 2015:

ok so my specs for my pc are:

Mobo: GA-F2A78M-HD2

Ram: Kingston hyperx fury 1600 ddr3

cpu: AMD A10-6800K APU 4.1 Ghz

gpu: gtx 750 from msi, It was referbished by newegg when i got it if that helps

and psu: logysis 330 watt (not sure what the brand name is but it came with the case i have

anyway, i've ruled out the gpu, and i've switched the ram in the whole 2 slots on my mobo, this seemingly did nothing, so either my motherboards ram slots are both broken or none of them are broken, i'm inclined to choose the later

I ran memtest86, this told me no errors were found with the ram it'self, so im left with the psu, or the cpu

I have no idea how to test for it being a cpu issue...although i'm not even entirely sure it's possible to have a cpu error and still boot the computer at all, but iv'e been wrong before.

This leaves me with a PSU problem...or something else i've overlooked...

at some point soon i will switch out the psu for a 1000 watt for testing purposes, if it fixes the problem, or for that matter if it doesn't ill make sure to report my findings here.

Ryan Hutzel (author) from Greencaslte, PA on November 19, 2015:

@Firehawk4nzz, Have you ran memory check for the memory itself... I would be weary of this being the PSU, but you also did not list everything that is in your computer and what PSU wattage and amperage you are running either.

Firehawk4nzz on November 18, 2015:

Ok so...I hope you guys can confirm weather or not this is the case, but for a few weeks now my computer has been randomly turning off, or BSOD, just crash, reboot, repeat.

However when it does crash, when it reboots the memory is cut in half. I have 1 stick of 8GB, and when my pc reboots it only says 4 is available

...originally i thought it was a cooling issue, but my temps average around 35 degrees so, thats not it, then i checked that maybe the gpu was the problem, so I uninstalled that, and ran of the integrated gpu on my mobo, that seemily showed no improvement, as my computer still crashed, and memory isn't the problem because if it was, the pc shouldn't boot at all, much less at full capacity to begin with.

(I'd like to clerify that, booting fresh, allows the full ram to load up, although just recently the pc crashes before it can even boot's quite infuriating)

A buddy from work says he had the same problem and bought a new more powerful psu(1000 watt), and that solved his problem.

I'm running the normal components of my pc and a gtx 750 off of a 330 watt psu, according to the specs, the whole build should only be using 250 ish and this just started happening recently this the sign of a failing psu?

Martin Caldera on September 07, 2015:

Hi friends, There are 3 simpthoms that tells you, that your PSU is about to die:

1.-Your Pc screen shows BSODs.

2.-Your DVD burner opens slow or do not opens.

3.-It tries but won´t boot properly.

4.-Your HDD makes strange sounds, in this case you unplug the DVD burner, and if it boots properly with no weird sounds from HDD, you can sure tell its the bad PSU.

Once you´ve changed your bad PSU, all three disappear for good.

Sorry for the grammar.

Adam on August 31, 2015:

So I'm trying to figure out why my HDDs keep dying. My symptoms came slowly. At first the graphics began bugging out while playing games (I suspect it's due to my power-hungry GPU) and my HDD made a noise every now and then. It slowly got worse and worse until the computer began freezing and forcefully rebooting. Soon thereafter, It froze during a game, turned off, and reported hard drive failure upon reboot.

I assumed at first it was HDD failure alone and replaces it, only to have failure a week later. The exact same symptoms as before, only much more rapidly. At that point I thought there may be an underlying cause.

The bugginess of the graphics during games around the time of failure lead me to suspect the GPU was hogging power away from other components. The HDD probably wrote corrupt data from a lack of voltage.

I can't test the PSU under load because without a drive, I can't run the GPU. Is it possible for a power supply to be partially dead and provide less power than it was built for? Or is there another issue?

gameguru on October 30, 2011:

How do I tell if it is a junky PSU?

Read reviews and find out how much power your system will use or find a PSU calculator, then find a reputable supplier and check the specifications on the PSU you want to buy or buy a PSU from a dedicated company in the power supply market, generally most top manufacturers make good power supplies and it is only high end enthusiasts and gamers who are concerned with figures of how one supply slightly excels another, for standard PC use you don't need to be concerned too much over numbers unless overclocking or fine tuning for high end use, gameguru.

TGWOH on July 11, 2009:

Stumbled on this article. Devoured it with glee. Thanks.

My 3.3 volt rail is low (2.8v). I will replace the 300 watt PSU. I shop locally and online. Everyone selling them says what they sell is not junk.

PSUs on the shelf 2 years ago cost $75. Now those same PSUs cost $20 with the same warranties ranging from 6 months to 2 years.Most then and now are made in China and meet US certifications.

So how do I tell if it is a junky PSU?

LondonGirl from London on January 13, 2009:

very helpful, thanks

katyzzz from Sydney, Australia on January 13, 2009:

Interesting information, keep on informing us.