PC shuts down and randomly reboots itself, don't know why.

So recently me and my brother built two computers with the same exact specs and everything.
One of the computers works fine.

The problem is simply that sometimes the computer will just shut down, and then reboot itself after 2-3 seconds.

SPECS:
GTX 970 (From our old pc's)
i7-8700K
PRIME Z370-P
TX850M Corsair
H60 Corsair
16GB Ballistix RAM

So after a while of this happening I have noticed a clear pattern, and that is it crashes when it’s under load, and it also depends on how long the computer has been on.
If I’m not playing any intensive games or doing other intensive stuff I can go for days without a single crash. (However I have noticed that a few things that didn’t cause the crash before, now will cause a crash). Like playing Fortnite.

What I've done so far:
Tried to replace the CPUs on the computers and still experiencing crashes.
And we have also replacing the RAMs and that also didn’t help.
And they of course do work inside the other computer. So they obviously haven’t been at fault.
We also put new thermal paste on.

Another thing that I've done is that I have re-installed and updated my graphics driver with Geforce Experience. I’ve all the "Ez windows 10 fixes" you find on a bunch of websites.
And I've tried unplugging my second monitor and using a different extension cable as I thought the power might've been the problem.
I've checked my computer for viruses, none found.
Took the computer to the repair, they told me they couldn't even get it to crash.
Not sure what they even did or if they just led it ran or something.

The whole build is not less than three months old and I’ve seen people saying that the PSU could be at fault, but it should be powerful enough as the other computer is running fine.
Capels are placed inside nice and secure. But maybe I’ve done something that could’ve changed how much power it’s letting out and such. But not sure how I can check if my PSU is the problem.

Also I know that heat might be the problem, but we put on new thermal paste on both of them. And I only have one monitor, so I don’t know how to check it when I’m playing to see.

Really appreciate any help I can get.
Thank you Less Than Three. (<3)
13 answers Last reply
More about shuts randomly reboots
  1. download and use realtemp program and see what the temps are at idle & load. Youll be able to see if its thermal issue
    if not then its most likely the PSU.
  2. What Fredfinks suggested is good to try. Temps are #1 issue for shutdowns, but reboots could be power related. If it tested fine at the repair place, my guess would be to try the computers on a different plug in at your house. Also, if you use a power bar, try a new one (not a bargain big one either, buy one that costs more than $10). I've seen grounding issues cause reboots simply by touching the case, or cause random reboots. A good power bar should indicate if it has proper ground by and LED indicator. If you have a power bar that has this, make sure the light is on solid, not flickering. If it's flickering, try another outlet in your house.
  3. Currently testing my heat, also did a BIOS rest because I know that I changed some stuff in the past. I'll report back once I know more. Thanks for the replies, really appreciate it.
  4. Pat Flynn said:
    What Fredfinks suggested is good to try. Temps are #1 issue for shutdowns, but reboots could be power related. If it tested fine at the repair place, my guess would be to try the computers on a different plug in at your house. Also, if you use a power bar, try a new one (not a bargain big one either, buy one that costs more than $10). I've seen grounding issues cause reboots simply by touching the case, or cause random reboots. A good power bar should indicate if it has proper ground by and LED indicator. If you have a power bar that has this, make sure the light is on solid, not flickering. If it's flickering, try another outlet in your house.

    So the computer just did a crash the fastest it has ever done. About 5 min in and I was downloading a Fortnite update, I was looking at the heat and it was around 10C when it crashed according to the log file. I'm going to try and plug the cables into another outlet in my room and see how it goes.
  5. Random reboots or shutdowns are mostly caused by 2 issues:
    1. CPU/GPU overheats and to prevent any damage, system shuts down.
    2. PSU fails to deliver enough power to the GPU or fails to keep smooth enough voltage for PC's operation.

    As suggested above, check your temps, both idle and under load. When your temps are within reason, it's the PSU who is acting up.

    While your PSU has enough wattage for your system and Corsair TXm is great quality PSU made by Great Wall, there are still some lemons, even among the best. In this case, my best guess is that your PSU voltage regulation has sifted outside of the ATX PSU standard specs of 5% on all rails (10% on -12V rail) and your PSU can't sustain stable enough voltage for your PC's operation. That's why your PC reboots at random times.

    Only fix is to get a new PSU. Either RMA your Corsair unit and get a replacement or if you don't trust Corsair anymore, go with Seasonic unit in 600W range. Why 600W range and not 750W? Because your GPU is 145W and if you add the rest of the system to it at 200W, total would be about 350W. 650W PSU is more than enough for your PC.

    E.g M12II-620 EVO, G-650, Focus+ 650 or PRIME 650 80+ Titanium,
    pcpp: https://pcpartpicker.com/products/compare/WrNypg,Tc3RsY,R7V48d,nn648d/

    M12II EVO and G series PSUs come with 5 years of OEM warranty. (My Haswell build is also powered by M12II EVO series PSU.)
    Focus+ is the newest PSU line from Seasonic and it comes with 10 years of OEM warranty.
    While PRIME 650 80+ Titanium is the best 650W PSU money can buy at current date.

    With Seasonic PRIME 80+ Titanium series, you'll get the highest efficiency (94%), tightest voltage regulation (0.5%), longest hold-up time (30ms), lowest ripple noise (20mV) and longest warranty (12 years) there is. Fully modular cables and toggle-able Premium Hybrid fan control too.
    specs: https://seasonic.com/prime-titanium
    review: http://www.tomshardware.com/reviews/seasonic-prime-titanium-650w-psu,4690.html

    My Skylake build is also powered by PRIME 650 80+ Titanium PSU (full specs with pics in my sig).
    Oh, all semi- and fully-modular Seasonic PSUs are also compatible with CableMod SE-series custom sleeved power cables. To match my Skylake's black & red theme and Haswell's black & blue theme, i have replaced the stock black power cables with CableMod SE-series custom sleeved power cables (red colored for Skylake and blue colored for Haswell).
    cablemod: https://cablemod.com/products/?filter_series=se-series&show_products=48
  6. Aeacus said:
    Random reboots or shutdowns are mostly caused by 2 issues:
    1. CPU/GPU overheats and to prevent any damage, system shuts down.
    2. PSU fails to deliver enough power to the GPU or fails to keep smooth enough voltage for PC's operation.

    As suggested above, check your temps, both idle and under load. When your temps are within reason, it's the PSU who is acting up.

    While your PSU has enough wattage for your system and Corsair TXm is great quality PSU made by Great Wall, there are still some lemons, even among the best. In this case, my best guess is that your PSU voltage regulation has sifted outside of the ATX PSU standard specs of 5% on all rails (10% on -12V rail) and your PSU can't sustain stable enough voltage for your PC's operation. That's why your PC reboots at random times.

    Only fix is to get a new PSU. Either RMA your Corsair unit and get a replacement or if you don't trust Corsair anymore, go with Seasonic unit in 600W range. Why 600W range and not 750W? Because your GPU is 145W and if you add the rest of the system to it at 200W, total would be about 350W. 650W PSU is more than enough for your PC.

    E.g M12II-620 EVO, G-650, Focus+ 650 or PRIME 650 80+ Titanium,
    pcpp: https://pcpartpicker.com/products/compare/WrNypg,Tc3RsY,R7V48d,nn648d/

    M12II EVO and G series PSUs come with 5 years of OEM warranty. (My Haswell build is also powered by M12II EVO series PSU.)
    Focus+ is the newest PSU line from Seasonic and it comes with 10 years of OEM warranty.
    While PRIME 650 80+ Titanium is the best 650W PSU money can buy at current date.

    With Seasonic PRIME 80+ Titanium series, you'll get the highest efficiency (94%), tightest voltage regulation (0.5%), longest hold-up time (30ms), lowest ripple noise (20mV) and longest warranty (12 years) there is. Fully modular cables and toggle-able Premium Hybrid fan control too.
    specs: https://seasonic.com/prime-titanium
    review: http://www.tomshardware.com/reviews/seasonic-prime-titanium-650w-psu,4690.html

    My Skylake build is also powered by PRIME 650 80+ Titanium PSU (full specs with pics in my sig).
    Oh, all semi- and fully-modular Seasonic PSUs are also compatible with CableMod SE-series custom sleeved power cables. To match my Skylake's black & red theme and Haswell's black & blue theme, i have replaced the stock black power cables with CableMod SE-series custom sleeved power cables (red colored for Skylake and blue colored for Haswell).
    cablemod: https://cablemod.com/products/?filter_series=se-series&show_products=48



    Thanks a bunch.
    We've done a few extra things, and if it doesn't work. We will try and replace the two PSU's and see if the other computer starts to crash.
    I'll report back once I know more.
  7. Aeacus said:
    Random reboots or shutdowns are mostly caused by 2 issues:
    1. CPU/GPU overheats and to prevent any damage, system shuts down.
    2. PSU fails to deliver enough power to the GPU or fails to keep smooth enough voltage for PC's operation.

    As suggested above, check your temps, both idle and under load. When your temps are within reason, it's the PSU who is acting up.

    While your PSU has enough wattage for your system and Corsair TXm is great quality PSU made by Great Wall, there are still some lemons, even among the best. In this case, my best guess is that your PSU voltage regulation has sifted outside of the ATX PSU standard specs of 5% on all rails (10% on -12V rail) and your PSU can't sustain stable enough voltage for your PC's operation. That's why your PC reboots at random times.

    Only fix is to get a new PSU. Either RMA your Corsair unit and get a replacement or if you don't trust Corsair anymore, go with Seasonic unit in 600W range. Why 600W range and not 750W? Because your GPU is 145W and if you add the rest of the system to it at 200W, total would be about 350W. 650W PSU is more than enough for your PC.

    E.g M12II-620 EVO, G-650, Focus+ 650 or PRIME 650 80+ Titanium,
    pcpp: https://pcpartpicker.com/products/compare/WrNypg,Tc3RsY,R7V48d,nn648d/

    M12II EVO and G series PSUs come with 5 years of OEM warranty. (My Haswell build is also powered by M12II EVO series PSU.)
    Focus+ is the newest PSU line from Seasonic and it comes with 10 years of OEM warranty.
    While PRIME 650 80+ Titanium is the best 650W PSU money can buy at current date.

    With Seasonic PRIME 80+ Titanium series, you'll get the highest efficiency (94%), tightest voltage regulation (0.5%), longest hold-up time (30ms), lowest ripple noise (20mV) and longest warranty (12 years) there is. Fully modular cables and toggle-able Premium Hybrid fan control too.
    specs: https://seasonic.com/prime-titanium
    review: http://www.tomshardware.com/reviews/seasonic-prime-titanium-650w-psu,4690.html

    My Skylake build is also powered by PRIME 650 80+ Titanium PSU (full specs with pics in my sig).
    Oh, all semi- and fully-modular Seasonic PSUs are also compatible with CableMod SE-series custom sleeved power cables. To match my Skylake's black & red theme and Haswell's black & blue theme, i have replaced the stock black power cables with CableMod SE-series custom sleeved power cables (red colored for Skylake and blue colored for Haswell).
    cablemod: https://cablemod.com/products/?filter_series=se-series&show_products=48




    So I'm 99% sure the PSU is at fault here and I'm going to order a new one. And I was wondering if it was still okay to use the computer even tho it crashes sometimes. Or will it cause damage to the computer in the long run?
  8. Since PSU is the most important component inside the PC because it powers everything, i wouldn't continue using the faulty PSU.

    There's no telling how far the PSU is gone bad and the least you can expect from those random reboots/shut downs is the data corruption on your drives while the worst is that PSU will fry everything it's connected to.

    So, if you don't want to replace your high-end hardware just so that you can get few days of usage out of your faulty PSU, don't power the system on until you've replaced your faulty PSU.
  9. Aeacus said:
    Since PSU is the most important component inside the PC because it powers everything, i wouldn't continue using the faulty PSU.

    There's no telling how far the PSU is gone bad and the least you can expect from those random reboots/shut downs is the data corruption on your drives while the worst is that PSU will fry everything it's connected to.

    So, if you don't want to replace your high-end hardware just so that you can get few days of usage out of your faulty PSU, don't power the system on until you've replaced your faulty PSU.


    So I swapped out my PSU from the one in the other computer, and today it crashed again.
    Do you have any other ideas on what might be the problem, thanks again.
  10. jappanini said:
    Aeacus said:
    Since PSU is the most important component inside the PC because it powers everything, i wouldn't continue using the faulty PSU.

    There's no telling how far the PSU is gone bad and the least you can expect from those random reboots/shut downs is the data corruption on your drives while the worst is that PSU will fry everything it's connected to.

    So, if you don't want to replace your high-end hardware just so that you can get few days of usage out of your faulty PSU, don't power the system on until you've replaced your faulty PSU.


    So I swapped out my PSU from the one in the other computer, and today it crashed again.
    Do you have any other ideas on what might be the problem, thanks again.


    A shot in the dark, but maybe try running the computers on a UPS (battery backup unit). Buy one with pure sine-wave inverter (Cyberpower makes one), run the tower on the plug-ins that are labeled as surge protect+battery backup. If it still crashes, return the UPS. But it'll sort out any power problems you have, as long as there isn't a ground fault.
  11. Either you are very unlucky where both of your PSUs are somewhat faulty or like Pat Flynn states, you have issues with the electrical grid.

    Without knowing the state and stability of your electrical grid, i can't tell if the fault is with your electrical grid or not. And without UPS to test it out, we can't be sure of that.

    It's a bit of long shot but here, i think that you experience blackouts that are longer than 17.7 milliseconds. Why 17.7 milliseconds? Because Corsair TX850m has hold-up time of 17.7 milliseconds, which means that your PSU can keep your PC running for that amount of time before it fails. If there is a power loss that is longer than 17.7 milliseconds, e.g 25 milliseconds then your PC will loose the power momentarily and it will reboot.
    Note: 1 second = 1000 milliseconds and since 18 milliseconds is so short amount of time, you can't actually tell that you had a blackout. To put it into perspective, average human brain registers visual changes in every 250 milliseconds, audio changes in every 170 milliseconds and touch changes every 150 milliseconds.

    If the issue is with your electrical grid then UPS will eliminate all problems that are caused by the electrical grid. Those include: blackouts (power loss), brownouts (voltage drop) and surges (voltage increase). Though, in my honest opinion, all PCs should have an UPS and i suggest you also get one for your PC.

    Good UPS brands to go for are CyberPower, TrippLite and APC.
    Note: The more powerful UPS you have, the longer UPS can keep your PC running before it's battery is empty.

    When looking for a UPS, there are 2 things to look out:
    1. Output waveform (square wave, simulated sine wave and true/pure sine wave)
    2. Design (stand-by, line-interactive and online)

    From here you can read about the differences between output waveform,
    link: http://www.minutemanups.com/support/pwr_un10.php

    And here are explanations about the UPS design,
    stand-by: http://www.pcguide.com/ref/power/ext/ups/typesStandby-c.html
    line-interactive: http://www.pcguide.com/ref/power/ext/ups/typesLineInt-c.html
    online: http://www.pcguide.com/ref/power/ext/ups/typesOnLine-c.html

    My Skylake and Haswell builds are also running off from UPSes where both PCs have their own UPS. I have two of these in use: CyberPower CP1300EPFCLCD (1300VA/780W, true/pure sine wave, line-interactive),
    specs: https://www.cyberpower.com/hk/en/product/sku/CP1300EPFCLCD

    While my PC is on idle/web browsing, my UPS runtime is about 35 mins. On full load, my UPS can keep the PC running at about 15 mins or so.

    Since your PC's power draw is about 350W and if you add monitor to it at (let's say) 50W then total would be around 400W. Here, the 1300VA/780W UPS would be more than enough for your PC with plenty of headroom for longer UPS runtime. You can also go for less powerful UPS, e.g 900VA/580W to save some money but don't go too low, else-ways you'll overload the UPS and UPS won't work (it gives beeping error code). Also, make sure the UPS has the right outlet type for your location. For example, my UPSes have 6x Type F outlets (aka Schuko) since i live in Europe.

    If you still get random reboots after your PC is running off from UPS then i'm lost. Only thing that i can think of at this point is the MoBo voltage regulator circuit.
    MoBo voltage regulator circuit is in charge of taking the voltage provided by the PSU (mostly +12V) and converting it into the appropriate voltage required by the CPU, RAM, chipset and other circuits. And if it's acting up, it could cause random reboots. Though, throughout all of my years in PC hardware sector, i have never seen MoBo voltage regulator circuit to be the source of the problem but that doesn't mean it isn't possible.
  12. Aeacus said:
    Either you are very unlucky where both of your PSUs are somewhat faulty or like Pat Flynn states, you have issues with the electrical grid.

    Without knowing the state and stability of your electrical grid, i can't tell if the fault is with your electrical grid or not. And without UPS to test it out, we can't be sure of that.

    It's a bit of long shot but here, i think that you experience blackouts that are longer than 17.7 milliseconds. Why 17.7 milliseconds? Because Corsair TX850m has hold-up time of 17.7 milliseconds, which means that your PSU can keep your PC running for that amount of time before it fails. If there is a power loss that is longer than 17.7 milliseconds, e.g 25 milliseconds then your PC will loose the power momentarily and it will reboot.
    Note: 1 second = 1000 milliseconds and since 18 milliseconds is so short amount of time, you can't actually tell that you had a blackout. To put it into perspective, average human brain registers visual changes in every 250 milliseconds, audio changes in every 170 milliseconds and touch changes every 150 milliseconds.

    If the issue is with your electrical grid then UPS will eliminate all problems that are caused by the electrical grid. Those include: blackouts (power loss), brownouts (voltage drop) and surges (voltage increase). Though, in my honest opinion, all PCs should have an UPS and i suggest you also get one for your PC.

    Good UPS brands to go for are CyberPower, TrippLite and APC.
    Note: The more powerful UPS you have, the longer UPS can keep your PC running before it's battery is empty.

    When looking for a UPS, there are 2 things to look out:
    1. Output waveform (square wave, simulated sine wave and true/pure sine wave)
    2. Design (stand-by, line-interactive and online)

    From here you can read about the differences between output waveform,
    link: http://www.minutemanups.com/support/pwr_un10.php

    And here are explanations about the UPS design,
    stand-by: http://www.pcguide.com/ref/power/ext/ups/typesStandby-c.html
    line-interactive: http://www.pcguide.com/ref/power/ext/ups/typesLineInt-c.html
    online: http://www.pcguide.com/ref/power/ext/ups/typesOnLine-c.html

    My Skylake and Haswell builds are also running off from UPSes where both PCs have their own UPS. I have two of these in use: CyberPower CP1300EPFCLCD (1300VA/780W, true/pure sine wave, line-interactive),
    specs: https://www.cyberpower.com/hk/en/product/sku/CP1300EPFCLCD

    While my PC is on idle/web browsing, my UPS runtime is about 35 mins. On full load, my UPS can keep the PC running at about 15 mins or so.

    Since your PC's power draw is about 350W and if you add monitor to it at (let's say) 50W then total would be around 400W. Here, the 1300VA/780W UPS would be more than enough for your PC with plenty of headroom for longer UPS runtime. You can also go for less powerful UPS, e.g 900VA/580W to save some money but don't go too low, else-ways you'll overload the UPS and UPS won't work (it gives beeping error code). Also, make sure the UPS has the right outlet type for your location. For example, my UPSes have 6x Type F outlets (aka Schuko) since i live in Europe.

    If you still get random reboots after your PC is running off from UPS then i'm lost. Only thing that i can think of at this point is the MoBo voltage regulator circuit.
    MoBo voltage regulator circuit is in charge of taking the voltage provided by the PSU (mostly +12V) and converting it into the appropriate voltage required by the CPU, RAM, chipset and other circuits. And if it's acting up, it could cause random reboots. Though, throughout all of my years in PC hardware sector, i have never seen MoBo voltage regulator circuit to be the source of the problem but that doesn't mean it isn't possible.


    So what I just did was that I changed the location of where the two computers were located, and tried using it again.
    And I got a crash about five minuts into gaming a bit of Fortnite. Also I used the mouse, keyboard, headset, and so on. So they aren't causing the problem either.
    But what I'm thinking, is that this means getting a UPS won't work,
    considering that I'm now on the same outlet that the other used. And using all the cables from the other computer.
    Or maybe I have misunderstod something, idk at this point, so blank as I can ever get.
    Thanks again, really appreciate the continuous help.
  13. If you do have problems with electrical grid then UPS and/or gasoline/diesel powered generator are the 2 things that help.

    What UPS is, is basically a big battery that has it's own charger built in and it charges the battery whenever there's power. When the main power fails, the power is drawn from the battery and PC normal operation continues without you even noticing power failure if the UPS wouldn't beep and let you know about it.

    This CyberPower video tutorial is a great way to understand what UPS is and how it works,
    youtube: https://www.youtube.com/watch?v=-IURKCvLJpY

    Note: Both of my UPSes are from PFC Sinewave series.
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