Can a split-second power outage shut off my PC?

[sew333]

Hello.
My pc:
10850K stock 4800mhz stock Kraken X73 good temps
2x16 GB DDR4 GSKILL 3000mhz XMP
Seasonic Tx-850 Ultra Titanium
Gigabyte Rtx 3090 Gaming OC
Aorus Z490 Pro Gaming
1 TB SSD

I wanna ask about something. So i plugged my pc in march 2021. All is fine. No pc shutdowns,reboots,pc stable. Had one power outage in june.
But 3 days ago, my pc suddenly shuts off during launching Metro Exodus Enhanced just after cinematic part.
I was wondering if that was my psu or very short for split second power outage?

I had laptop connected to other power cord but laptop doesnt go to battery mode in this moment ( i checked event logs ). Also router plugged to wall dont disconnect internet.
And my question is. It was so short power outage for a brief second that only pc went off or it was my psu? Thank you.

All working fine no shutdowns actually. I tested all games no issues now.

 

[Darkwood]

If your pc has no battery back up like a laptop then yes, it's called a brown out and depends on the voltage drop and how long, most electronic devices have stabilisers like capacitors that can maintain the voltage for a few seconds but depends on the demand of the device... if you are gaming it will be heavy demand and crash.

 

[sew333]

So its was possible that was brownout and pc goes off when other appliances not?

 

[pc1966]

So its was possible that was brownout and pc goes off when other appliances not?

Yes.

Typically a PC is specified to hold up for half a supply cycle(around 8-10ms) and if you need to survive more than that then you need to look in to a UPS for outages or drops in voltage lasting up to several minutes to hour-ish, and for longer periods a backup generator to feed the UPS for longer periods (with the UPS holding up for the time it takes for the generator to start and come on-line).

 

[sew333]

But why router dont disconnect to off and internet was on? Also was laptop was still on <not in battery mode>. Only pc went off.

 

[pc1966]

Reading what you said again, if it shuts down when you start some application it really sounds like the PSU is not up to it. Either a poor connection or it is under-rated for the stuff you have.

 

[pc1966]

But why router dont disconnect to off and internet was on? Also was laptop was still on <not in battery mode>. Only pc went off.

If it were an external event then it just depends on the loads, etc. A router taking very little power might last a couple of mains cycles, something else that is barely holding up could go on the first 1/2 cycle missed.

 

[sew333]

I know but i tested 100 times the same scenarios when launching game and psu not shutted off.

 

[pc1966]

With a single event you can't really tell.

Even if you think nothing has changed there is always the chance it was some software update that alerted loading, etc.

If it starts happening more then I would suspect the PC PSU (more if happening on doing something). In more than half of the failed PCs I have seen it was just the PSU that needed replacing.

 

[sew333]

When pc is running i switched off power cord button for split second and then again turn on and pc just restarting,not shutdown like earlier. So propably it was psu issue not brownout?

 

[pc1966]

When pc is running i switched off power cord button for split second and then again turn on and pc just restarting,not shutdown like earlier. So probably it was psu issue not brownout?

You are right that usually it would restart, I had not realised that you meant it went off and stayed off.

Maybe it overheated and the BIOS powered it down? Do you have any means to check the various temperatures while it is running? (Not so familiar with Windows but for Linux there are tools like lm_sensors to show the internal voltages, temperatures, and fan speeds).

 

[sew333]

I run few games now for 24 hours and no shutdown. I am start to thinking that power in house was issue. Is this possible that a momentary outage was in only one socket in room? When rest had the power. or not?

 

[sew333]

I just wanna ask. If that was brownout then all appliances will be affected,like router and laptop ( no battery mode ,power mode ) ,pc. Or only pc?

 

[pc1966]

I just wanna ask. If that was brownout then all appliances will be affected,like router and laptop ( no battery mode ,power mode ) ,pc. Or only pc?

It very much depends. Most power supplies are designed to hold up for a 1/2 cycle of the supply, but that can be longer if the PSU is under part load compared to the design. for many cheaper appliances "the design" is normal operations and no additional margin.

I very much doubt it was a supply issue as usually you would notice the lights flicker, etc. It could just be a bad connection at that particular outlet, but then normally tapping or wiggling the power cord would provoke it.

Also as discussed above, most brown-out events trigger a reboot by design (basically the CPU is held in reset until all supply rails are OK) so if it simply went off, it is more likely an odd PC fault, an overheating event, or some bug in the operating system crashing the CPU in a manner that evaded the BSOD that normally happens on kernel faults with Windows.

 

[sew333]

So if router and laptop was not affected then propably pc issue and not brownout?

 

[pc1966]

So if router and laptop was not affected then propably pc issue and not brownout?

Probably.

But the laptop has an internal battery so unlikely to notice it. However, I have had one shut down on momentary power fail as it had not had any keyboard/mouse action, even though it was busy with network traffic / SSH sessions, as the power management was set to power off on battery after X minutes of being idle!

 

[sew333]

So propably pc related? Because if that was brownout pc should reboot not shutdown? Also when i switch fast off/on button on power cord pc rebooting not shutting down.

 

[sew333]

When i cut power for 1 second in power cord by button OFF/ON pc rebooting,fine.



Week ago i had shutdown of pc during launching game. And i dont know if that was psu or brownout issue. Pc shutdown,not rebooted.



And my question is. Is any difference to pc between brief brownout and switching fast OFF/ON button in power cord? If that was brownout pc should reboot too?