So I have a UPS or PSU problem?

[Thinker_145]

I have a 1000W UPS powering my computer, monitor and router. I sometimes experience power shutdowns so the UPS gives me enough time to save anything I am doing. However today I think for the first time there was a power shutdown while I was playing a game. My PC "restarted" and showed this message,

Now the power is still out and the PC is still running. I pressed F1, got into the BIOS and then got into Windows as well all the while the power is out and UPS is running. So the UPS can't be at fault here can it? Just to make sure the UPS isn't getting overpowered I later ran a stress test, turned off my monitor and then shut off power for a few seconds before restoring it. I still got the same screen as above.

If the power loss occurs while the system is not under stress nothing happens and everything keeps running smoothly with the monitor on till the UPS has the juice.

However if this is just a PSU problem then why is it never a problem when there is power? I mean if a PSU is underpowered or malfunctioning then it should show problems whenever the system is stressed which I have never ever experienced yet. If there is a power loss then what does that have to do with the PSU? But then the UPS should have zero issues in terms of pure power with my computer at full load without the monitor in the equation.

So could it just be that the ASUS board is being "over smart"? Is it safe to try to see what happens in the event of a power loss after turning off ASUS anti surge support?

EDIT: Just to remove any doubt about the UPS' capacity being enough for my PC at load I plugged in my speakers to the UPS, full on blasted them and cut off the power. For 10 seconds everything was going smooth the speakers, the monitor and the idle PC playing music. I restored power after that so I suppose the UPS really is off the hook I would think.

So it's between the PSU and motherboard?

 

[Hail The Brain Slug]

It may have had something to do with the fact your PC was loaded as you were playing a game.

Looking up your PSU, it appears to have been released in 2010 so it may be as old as 6 years. For a decent quality unit like that, it's very likely beginning to lose capacitance and its ability to supply higher loads. If its power delivery capability is reduced, its hold-up time might be low enough it couldn't survive the switchover from AC to battery with the load it was supplying.

I would test cycling it again with your PC under a heavy load like ASUS Realbench (It hits CPU and GPU and does a pretty good job at power draw). If it only happens when your PC is loaded, I would think it's most probably your power supply.

 

[WaywardSon]

Do you have a spare psu to test in there? If it's the MB, it should give you the same error message. If not, then your PC should power normally and you know it was a defective psu.