Occasional whole shut downs and restarts

Soldato
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This is an odd one. Very occasionally, my computer will restart itself with no warning. It doesn't shut down correctly, it just goes straight to black screen and then the BIOS loading screen.

It's usually when a game is being played or being started up, so I wonder if it's related to load.

I'm pretty certain it isn't an overheating issue though. It sometimes happens when the computer has only just been started up for a start. And when it happens, it instantly restarts, and then has no issues at all.

Are there any other general issues which could cause this behaviour? It's actually been happening for months, but I've never got around to doing anything because it is so infrequent.
 
Soldato
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My crystal ball doesn't even power on, so what parts that coffee maker has eaten?
Because that could be caused by quite a few parts.

Also check Event Viewer and Reliability Monitor for any errors with times fitting to those problems.
 
Associate
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I am not an expert in such matters but peronsally I'd look at the PSU as a first port of call as in my experiance random restarts without warning and just instant turn offs have been PSU being either old or not up to the task.

As above though, Event Viewer and Reliability Monitor might be able to provide you with more information.
 
Soldato
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Thanks. Sorry for the lack of system detail, but I really didn't know which bits were likely to cause this, so didn't know what detail to go into.

I didn't know about the reliability monitor. It looks like it might have caught at least one of the failures. But I'm not 100% sure of the times and dates, so I'll wait for the next one and then check it.

If it is PSU, can I just pull that out and replace with a new one with reasonable ease?
 
Soldato
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That PSU is low end cheapo made from cheap parts and definitely too little for 1080 Ti.
650W quality PSU would be good minimum for it, unless CPU is very low end model.
(even then 550W PSUs come with only one PCIe pwoer cable)
And proper PSU certainly shouldn't be too expensive when you could afford that expensive graphics card.

Bitfenix Formula is pretty much minimum level for decent PSU.
https://www.overclockers.co.uk/bitfenix-formula-series-650w-80-plus-gold-power-supply-ca-22z-bx.html
But Antec Earthwatts is step up with better platform and comes with semi modular cabling for only little more.
https://www.overclockers.co.uk/ante...plus-gold-modular-power-supply-ca-24n-an.html

And really 10 year warranty Antec HCG Gold or Seasonic Focus Plus shouldn't bee too much considering price of 1080 Ti.
https://www.overclockers.co.uk/antec-hcg-gold-650w-80-plus-gold-modular-power-supply-ca-24w-an.html
https://www.overclockers.co.uk/seas...plus-gold-modular-power-supply-ca-05q-ss.html
(basically same PSU in different clothes)

Could have said that in the first reply, if you had listed components in starting post.
 
Soldato
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CPU is i7-8700k.

It's a pre-built system, and while I wasn't aware of it at the time I have read on here since that builders do sometimes cheap out on the PSU as it's not where the buyers focus.

(Certainly I thought that 550W seemed a bit low, but decided the manufacturer must know what they were about).

I've replaced various components before, but never a PSU. Is it likely to be something I can replace with reasonable ease? I do quite fancy going modular to tidy up the cabling a little.

I see the ones you've picked out are all 650W. Worth going higher again to be absolutely safe? I don't mind paying a bit extra to get the right thing.
 
Soldato
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Name and shame.

650w should be fine. Use an online calculator to work out watts.

I think you should get something that gives the PSU some headroom. PSUs have an efficiency profile so that's useful to consider.

Don't buy cheap. Check for Japan made capacitors on the main board.
 
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Associate
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I've replaced various components before, but never a PSU. Is it likely to be something I can replace with reasonable ease? I do quite fancy going modular to tidy up the cabling a little.

It should be pretty straight forward swap and modular PSUs are certainly easier to work with. Routing all the cables to keep them out of the way will probably be the most time consuming part depending on your case and how neat you choose to make it.
 
Soldato
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Thank you.

I don't think I can name and shame, as it's a competitor. Overall I'm very happy with the package they sold me. I got a system with a 1080Ti for only a little more than others were offering 1070 systems for. Obviously this is showing up a corner which was cut to allow that. And the case was a fairly cheap one too, but it seems fine. I was in a rush and had to go with a pre-built for next day delivery, otherwise I'd have specified better components myself.
 
Soldato
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Factory overclocked non-reference 1080 Ti is ~300W max power draw card.
https://www.techpowerup.com/reviews/ASUS/GTX_1080_Ti_Strix_OC/27.html
https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Gaming_X_Trio/27.html
https://www.techpowerup.com/reviews/MSI/GTX_1080_Ti_Lightning_Z/27.html

And while fully loaded 8700K could reach up to 150W power draw, if motherboard chases advertised clock speeds, game load is like halfway there.
So that puts max gaming draw to fair 400W - max 450W level.

High quality (what Corsair VS isn't) 550W PSU could handle that, but certainly goes over comfort zone.
For 650W PSU that would fit leaving some extra/reserve.
Though if you start overclocking 750W would be certainly justified.


PSU is one of the easier components to change.
Assuming one non-M.2 drive there's just five cables to detach.
And I don't think that shop used any really good CPU cooler, so also CPU power cable should be easy to reach.
(big coolers bury connecter under them)

You just have to use two separate cables for graphics cards.
Single cable with splitter in the end compromises voltage stability with higher 12V losses and also ground reference rising more above actual 0V.
(besides quadrupled power loss and heating of cable compared to same current shared between two cables)
 
Soldato
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Thanks for the tips. CPU cooler is an AIO water cooler, so I think the CPU should be easy enough to get at.

The slightly annoying bit (entirely self inflicted because of the timing of asking this question) is that I've just moved from the computer being on the floor to being within a desk cupboard. So to open it up I'll have to remove all the cables from the back to pull it out in order to get the side off. Still, that means I can do it properly laid on it's side on a table rather than crouching under my desk trying to shortcut the work. :)
 
Soldato
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Fitted it (the recommended Seasonic) in my lunch hour, and it all went pretty smoothly. The instruction manual was laughable (basically - turn it off, plug everything in, turn it on), but it was all pretty straightforward. Thanks for the tip to use two separate power lines to the graphics card though - I would totally have just used the split cables at the end of one otherwise without knowing any better.

I even managed to keep the cabling fairly tidy. The one complication was the CPU power. This is off to the edge of the motherboard, presumably to avoid issues with the cooler getting in the way. Except it means it's right up against the rad for the AIO water cooler instead. I had to remove that rad from the case temporarily to be even able to press the latches to remove the old power cables.

Anyone any idea what the 'hybrid' button on the back does? The manual doesn't mention it at all.
 
Soldato
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The Hybrid button switches between the fan profiles.

THE FAN CONTROL BUTTON
The fan control button can be found on the back of the back of the FOCUS PLUS power supply, next to the power switch. The image here illustrates how to select different fan control modes to suit your need.

DO NOT press the button if you wish to include the Fanless Mode, which means the fan in the power supply will not spin when the power supply is under light loads. Press the button if you wish to have the fan spin at all times, even at lower loads.

https://seasonic.com/focus-plus-gold

A tip for the next time you take the rad out. Get a 8 pin extension for the CPU power and feed it through the back of the mobo tray. Makes life a lot easier if you have to unplug it in the future.
 
Soldato
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OK, does anyone have any theories other than PSU? Had no issues since fitting the new one, until yesterday when the same symptom occurred, and it's just done it again today.

If it does sound very like a power issue, I wonder if it's possibly the power strip the computer is plugged into?
 
Associate
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OK, does anyone have any theories other than PSU? Had no issues since fitting the new one, until yesterday when the same symptom occurred, and it's just done it again today.

If it does sound very like a power issue, I wonder if it's possibly the power strip the computer is plugged into?

Are all the Windows updates installed? There were some microcode updates that were rolled out sometime last year that were causing random restarts (subsequently fixed with later updates).
 
Man of Honour
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If it isn't the PSU the most likely cause of sudden reboots without properly shutting down is because the CPU or RAM isn't stable - i.e. CPU voltage not high enough.

One of the first things I would do is a complete memtest.
 
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