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Computer Hardware - Why does my computer keep shutting off?

I recently replaced just about every component on my desktop computer:
CPU (AMD FX 8350 8-core processor)
Heat sink fan (because the one that came with the CPU was frickin loud)
16 GB RAM (8GB x 2)
Video card (MSI GeForce GTX 970)

I read that a computer shutting off suddenly can be related to components overheating, so I downloaded HWMonitor (a program that monitors your hardware and gives info like temperatures and fan RPMs). I do not see any unusual heat readings when the computer is running normally (e.g. browsing the web, running programs on the desktop). The problem usually occurs when I launch a game; so far it has happened with Assassin's Creed Unity and Far Cry 4.

I have not been able to get an accurate heat reading for other, less intense games that require fewer system resources, but I suspect the problem may actually lie in my PSU, which has a max output of 480W. I've used multiple online "power supply calculators" to see what they recommend given my setup. Every single one I've tried has given me different results for various reasons. For example, one tells me I would only need an output of 400W while another says I need over 500W. The one that I trust most is Newegg's, which tells me I need at least 1200W output.

I'm still kinda new to upgrading computers, so I'm wondering if someone with more knowledge about hardware can diagnose this problem. Let me know if you need more details on my configuration.

TL;DR is it time for a new power supply?
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Mikkel Sandberg
Asked:
Mikkel Sandberg
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9 Solutions
 
hulseboschSystem administratorCommented:
My first thought would be your power supply.
Have you checked the leds (if any) on your motherboard after a suden shut down?

At several types there will be one ore more lid, when powered.
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Mikkel SandbergFront End DeveloperAuthor Commented:
There's a green LED near the bottom of the mobo that's on when it's running smoothly. I haven't noticed it change color when one of these shut downs happens, but I suppose I could try reproducing the problem and see what happens :P

Don't really want to do that, but I may have to. I remember reading somewhere that there are programs that will stress test your computer for you. Do you know of any?
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dbruntonCommented:
Mersenne Prime Test

http://www.mersenne.org/download/

Read the documentation on the page and find the CPU Stress Section.
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Fred MarshallPrincipalCommented:
It's generally easy and not very expensive to replace the power supply.  In some sense, that's the best "test".

But, most usually, power supply failures will exhibit by not allowing the computer to turn on at all.  I've only seen a scant few that would start and still the problem being the power supply.

The other issue is motherboard capacitors.  These will also cause the computer to not run or to shut down.  I think that's the more likely situation here in view of what you've described.

If you inspect the motherboard, you can readily see bad capacitors.
There's a good picture at:
http://en.wikipedia.org/wiki/Capacitor_plague
The capacitors *may* have crud oozing out and *may not*.  It's the puffy tops that are the thing to look for.
You might replace the caps yourself if you can solder them adequately.  Or, there are services available such as at:
http://www.badcaps.net/
I've used this service and the results were good.
Nonetheless, it's a real decision whether to replace caps or to just give up on the mobo.  
You have to really want to save the mobo or the OS license or ..... to make it worthwhile.
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Mikkel SandbergFront End DeveloperAuthor Commented:
@hulsebosch
Have you checked the leds (if any) on your motherboard after a suden shut down?
The LED stayed green after powering off.

There is a new development though:
I decided to run the Windows Rating utility to update the rating after putting in my new graphics card. I'm not sure if that's exactly what it's called, but it's the program that's run when you right-click on My Computer and go to properties and it tells you what your computer's rating is. It seems like it runs a stress test of sorts to see how well everything performs.
Anyway, when I ran this, it shut down again! It probably has to do with the graphics card requiring more power than my PSU can handle.

What do you all think? Is this a plausible explanation? I was under the impression that a PSU failure resulted in a blue screen more often than not.
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hulseboschSystem administratorCommented:
It makes sence, do is not waterproof evidence. Only shows power down on stress.
Is it correct you have this problem sindse  your new videocard?
If so, whats the consumption difference with the old one?
Perhaps a vc with cooled processor?
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Fred MarshallPrincipalCommented:
There's nothing here about power down *on stress*, simply power down after an unspecified time.
But the notion that it may be overloading the power supply is a good one.

If I had 3 models which resulted in 400w, 500w and 1200w, I'd be very tempted to question the outlier.
Something is obviously wrong and it's likely in the inputs to the models.
Perhaps the questions they ask aren't clear.
Maybe you could share with us the models and the inputs you used and why?  Then we'd be able to comment on the models, their inputs and the results.
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Mikkel SandbergFront End DeveloperAuthor Commented:
I guess I wasn't very clear.

The problem does appear to be on stress, and I only have a 480W power supply on hand. The others I mentioned are what various online power supply calculators recommend that I should have given my setup. Sorry if that was clear.

I guess I should have figured that a new PSU would be in order when my new card required 2 6-pin power connectors, as opposed to 1 with my old card :/

Anyway, you guys have been really helpful, and it seems that the power supply is in fact the problem.
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_Commented:
I'd go with the beefier power supply. It sounds like the GPU is trying to use more 12 volt, than yours can supply.

I'd go with a 800W, minimum. One with a good 12v rating. I've been happy with Corsair for the last few years.
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Daniel FoyeCommented:
Without a doubt it is a lack of sufficient power. Get an 800 Watt or greater PSU and kiss your problems goodbye.
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Fred MarshallPrincipalCommented:
Indeed, the cost difference is generally negligible and there's really no such thing as "too much" capacity unless the power supply has a minimum current requirement just to properly operate.  I've heard of such but never encountered the problem.
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nobusCommented:
>>  Why does my computer keep shutting off?  <<  any component can cause this, but most common are :
-Power supply
-Ram
-disk

as for the power  - calculate what you need first - 480 W seems enough on first sight
here a link to a  free calculator  http://extreme.outervision.com/psucalculatorlite.jsp      

it is also useful to run ram and disk diags - i use the UBCD for this : http://www.ultimatebootcd.com/
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Fred MarshallPrincipalCommented:
The 6-pin PCI-e 12v connectors are generally supplied from two separate 12v sources ("rails") within the supply.  At least it seems strongly implied that ONE 12v source isn't adequate.  

So, in a practical sense, it will depend on the load connected to the 6-pin.  If the load is modest, then it won't matter if all the pins are powered from the same source.  If the load is more demanding then it well may matter.

There can be multiple 12v buses or rails in the power supply - which are each limited to their individual max current levels.  So, if one needs more than one of them can provide, you need more.  The 6-pin allows for 2 or even 3 sources.

I would not trust any of the adapter cables to give your what you need from the Molex 12v connectors necessarily.  
Many of these simply break out the 6-pin into TWO Molex connectors.  Then they leave it up to you where to plug in the Molex connectors.  The idea is to double up on the number of wires for current capacity.  I read, as above, that there are separate 12v rails powering a native power supply's 6-pin connector.  So, the idea is that you might use such an adapter but pay attention to where you plug in the 2 Molex and that the power supply can deal with the 12v needs.

It's way easier to get a power supply with its own 6-pin connectors.  I currently source Kentek ATX 650W Power Supply 20/24 PCI-e6 P4 w/Switch.  It's an inexpensive supply meant for generic replacements.  You can always spend more...

You didn't reveal your model numbers.  You say that the Newegg model suggested 1200W output.  It pays to use a little common sense with these things and not just trust "the numbers".  Here's a 1200W device:
http://www.air-n-water.com/product/w1212.htm?utm_source=google&utm_medium=comparisonshopping&utm_term=King&utm_campaign=Wall%20Heater&utm_content=W1212&gclid=CjwKEAiA28ilBRCy5cXrgtfTxTISJABgX7E21vm3rBFqwnMFFKBI0xVYq43IGfB5yBmW0haKBLLV6BoCg0vw_wcB
Obviously the purpose is a *room heater*!  Do you expect your PC to be putting out the same amount of heat?  If so then by all means.  But I doubt it.
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☠ MASQ ☠Commented:
The finger of blame can be clearly pointed at the GTX card here!

Although it runs normally at a really very low current draw for it's specification both the GTX 970 and 980 behave very differently once you start pushing them even with, by current standards, quite simple games engines.

The card is designed to optimize power consumption but a consequence of this is that when pushed it produces instantaneous spikes on its demand to the PSU as the capacitors on the board recharge.  If you have sufficient overhead on the PSU you won't notice this but without that "safety margin" the PSU will, for a fraction of a second, overload the rail and shut itself down.

Technical specs about this known issue are outlined here:
http://www.tomshardware.co.uk/nvidia-geforce-gtx-980-970-maxwell,review-33038-12.html

But the bottom line is, as posted already, you need to replace that PSU to accommodate the power consumption profile of your graphics card.
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AaronSystems Administrator & DSTCommented:
The best indicators for power consumption are CPU and the Graphics. For what you listed I would suggest a 750 watt power supply (crossfire or sli compatible in case you want to duel GPU later). You can go more but I would not go any less than 700W. It might be worth it to get something around 850W or more for if you plan to add lots of fans and other things. Most power supplys are high efficiency now and will only use what is needed. This is almost certainly a PSU issue.
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nobusCommented:
did you calculate yet what power you need?
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Mikkel SandbergFront End DeveloperAuthor Commented:
@nobus, yeah I used this calculator. It's a bit complex at times, so I'm not sure how accurate the results were. It told me I would only need 389W, so I'm thinking that I did something wrong.

I appreciate all the help and feedback; I think I have enough to go off here. I'm going to mark this question as answered, and if I have any more problems I'll post a new question.

You all seriously rock :)
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_Commented:
Thank you much.      : )
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nobusCommented:
>>  would only need 389W  <<   that is often the case; most people advise buying pS'es that are much too powerful
i always use their outcome, and advise to add 50 W as minimum Wattage, also for future upgrades
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AaronSystems Administrator & DSTCommented:
His current PSU has a max of 480W... Most any crossfire or SLI PSU will be over 650W and most decent graphic cards will suggest above 600W PSU for a single with either 6pin or 8pin connector... It is not good for a PSU to run at max load continuously either and often can get much warmer. It is better to get higher and only use 1/2 or 3/4 of max wattage. Most newer power supply units actually are very efficient in their usage and will only supply what is needed. Remember MAX does not mean it is suggested to run at all times.

[This specific graphics card actually says it requires a MINIMUM 500W power supply.
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nobusCommented:
Aaron there is no need for higher wattage at all; on the contrary, a PS best runs near  it's max wattage.
if he put the card in the calculator, the power need is included
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AaronSystems Administrator & DSTCommented:
I guess it depends on your preference. But obviously the 480W he has is not sufficient... Therefore how can you suggest to use an even lower one? And you need to look at the continuous not the max or peak output. Most power supplies hit their peak efficiency levels around 40 to 80 percent load. Therefore if you go with 50-70% being used for a computer then you have room enough to upgrade. Even if you look at Wikipedia you can see 50% loads have higher efficiency than 100% and just because you have a higher wattage PSU does not mean you are using the higher amount.

http://en.wikipedia.org/wiki/80_Plus

This is the spot where I found a more specific 40-80% load number as confirmation rather than just giving you arbitrary numbers based on my own experience.

http://www.pcworld.com/article/2025425/how-to-pick-the-best-pc-power-supply.html
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nobusCommented:
>>   But obviously the 480W he has is not sufficient  <<  where did you get that idea ?
and wikipedia link you posted says :  " it certifies products that have more than 80% energy efficiency at 20%, 50% and 100% of rated load,"   so why  do need a bigger one?  i see no reason

and the last link says "Building to about 50 to 60 percent of a PSU's capacity is advisable to achieve maximum efficiency and yet leave room for future expansion. " so it says to have a bigger one - - if you calculate on future expansions ; not because it's better at 50%

but thanks for debate - which i now will consider closed
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AaronSystems Administrator & DSTCommented:
I am not trying to be argumentive just help out the person who asked the question and make sure they get all the correct information. And I do not want people to think in general terms of "bigger is better" but rather "50-70% usage is best".

To clarify his current power supply (most people on here think that the power supply is the issue) is to quote the author "I suspect the problem may actually lie in my PSU, which has a max output of 480W". Assuming we can agree the issue is the power supply getting a lower max output would not help.

Wikipedia shows the % of efficiency in this table which I why I linked it:

Efficency output for PSU at 20 50 and 100 percent.
And yes an 80 rating means it gest at least 80% at each of those percentages but not that it performs at exactly 80 and it does not mean it peforms the same at each percentage.

The other link says "Most power supplies hit their peak efficiency levels with loads in the range of 40 to 80 percent." Meaning when they are only using 40-80% of their max output they perform the best.

And yes it says 50 to 60 but I said 50 to 70 to allow a larger range (their range would say to stay even farther from max output than what I suggested).
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