Computer shuts down by itself

Destyre

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May 18, 2011
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18,510
Hello,

I just upgraded from an Nvidia Geforce 8600GT to an ATI Radeon HD 5670. With the 8600 in, I was able to use a 400w PSU perfectly well, but it can't run the new card, so I put in a 600w power supply.

The problem I now have is that ONLY while I'm gaming, the PC will shut down after 20 minutes of so without warning. I did some research online and most people expect it to be heat, but my computer worked perfectly well with the older graphics card and power supply in. Further more, I have gone as far as to opening the side panel of my pc and pointing a huge desktop fan to blow air directly into the machine, but with no change with the problem.

The last time I tested my machine I used an AMD gadget for windows 7 which can monitor CPU heat. I kept an eye on the temperature as I ran a game on full graphics (which my new graphics card can easily handle without strain) and the temperature of the CPU remained below 30 degrees celcius, which is well within it's safe operating limits.

As the graphics card and power supply are the only new additions, and no matter what I do to optimise the airflow, I get the same problem, I now strongly suspect that the power supply is to blame.

A few things don't make sense though... if the power supply was to blame, why would it only shut down during gaming? (surfing the net, watching movies etc doesn't cause it to shut down) and secondly, is there any other part of the machine that might be overheating, aside from the CPU that might cause the computer to shut down?

I should point out that my pc did overheat somewhat with the old graphics card in, but I would hear a warning sound coming from my pc, then promptly would open up the case to let it breath, and all would be well. This time I'm getting no warnings at all...

Is it possible that there are some settings that are making my machine shut down like that, that maybe I don't know about?

With all the evidence, what is the most likely culprit?
 
Solution
What kind of PSU is it? There is a big difference in a quality 600w PSU, and a low quality 600w PSU. During gaming, you're stressing your video card more than during idle periods. The added demand for power could be a reason to blame the power supply.

Check the event viewer to see if there are any error logs being generated.
It is possible that the PSU is to blame, and that it is purely coincidental that it is now failing. The only way rule out the PSU is to test its votages. Use a multimeter to check it. Another possibility is that the thermal paste between the CPU and heatsink has dried up. If this were true, that fan you have pointed at your mobo wouldn't help, but I'd also suspect that if your CPU were in fact overheating, you wouldn't be able to turn the computer back on for several minutes.
 

Destyre

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Thanks for the reply.

With regards to the power supply that I'm using, it's really only the first time that I've used it, it's been sitting around in a box for about a year on my shelf. I just replaced my 400w with it, which worked perfectly using my Geforce, but seems to be unable to run my new card, even though on the box of the card it says that a 400w or higher PSU is required to run it.

The differences between the two, other than the wattage, are that the 600w has a fan that points internally into the machine, which the 400w has a fan which points at the back. I'm guessing that both are extractor fans. Not sure if that makes a difference or not. Also the power cable from the mains doesn't go all the way into the 600w socket. No idea why, but it fits in securely enough to stay...

I'm thinking that my 600w PSU is perhaps faulty. It is a "PC Power" brand only, a cheap one.
 
What kind of PSU is it? There is a big difference in a quality 600w PSU, and a low quality 600w PSU. During gaming, you're stressing your video card more than during idle periods. The added demand for power could be a reason to blame the power supply.

Check the event viewer to see if there are any error logs being generated.
 
Solution

Destyre

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On the box it says "PC Power Supply" beyond that there seems to be no brand. It was fairly cheap; about 20 euros. If I'm gaming and it stresses the PSU, does that mean I don't have enough wattage or that my PSU is just faulty?

Event viewer? I'm not familiar with that sorry, what is it?
 
To see the event viewer:
start-->run-->event viewer-->look in the system and application logs for red X's

Look at the side of the power supply for a label. It should look something like this:


How many +12v rails are there?
What is the current on the 12v rails?
What is the available power under the +12v rails?
What is the total power?

Or, even better, what is the power supply model?
 

Destyre

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With the event manager, all I found at the time of the shut downs was: "The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly."

With regards to the power supply, it has no brand on it. All it says in bold letters is "PC Case" Then next to that "600 PC" which I gather is the wattage.

with regards to the technical information, it is as follows:

AC Input: 115/230VAC 10A/5A 50/60hz
AC Output: 115/230VAC 2A/1A 50/60hz
DC output: +3.3v +5v +12v -12V +5VSB
DC output (written underneath the voltage values in this order): 30A (underneath +3.3v) 46A (underneath +5v) 24A (underneath +12v) 1A (underneath-12v) 2.5A (underneath + 5VSB)

Below that in small writing it says: "+5v& +3.3v SHALL NOT EXCEED 280W."
And then: "+5v& +3.3v& +12v SHALL NOT EXCEED 320W"

I copied as much info as I could as my cam is taking bad quality pictures. Sorry for any useless information, but I know next to nothing about electrical jargon. I suppose from that information the amount of 12v rails is 2? (a positive and a negative) the current for +12v looks like 24 amps. The small print stating that "+12v shall not exceed 320W" I guess would be the available power to +12v rails? Total power it doesn't say, I'm sorry.

I tried to find the brand using the model number, (which is this: PC CASE 600 PC ATX 2.2 (P4)
MODEL :LPK12 - 35P4)

Note that I'm using AMD, that P4 looks suspicious to me... and the +12v not exceeding 320w.... my graphics card needs 400w. Perhaps i just dont know what im talking about but I'm sure you can decipher it... :)
 
Its combined power is only 320W which is pretty sad for a "600W" unit, but unsurprising for a 20 euro unit. Replacing a low power PSU with a POS PSU doesnt do anything to help you. The 46A limit on the 5V rail tells me that this unit is an old ATX 1.x model that was given some additional cables like the 4 pin CPU power connector so it could work with a modern system, the problem is that its primary transformer cannot do more than 320W and thats probably at 25C, at 30-40C like its likely to be running its probably down to 250W.

Get yourself a good unit, if it costs you less than 50 you got yourself a paper weight or a firecracker.
 

Destyre

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Thanks for the reply... So it's definately the PSU you think? It's all greek to me, anything electrical related. I assumed that a 600w PSU would mean it gave me 600w power... stupid me!

If I were to buy a decent power supply which is good enough for what i need to run my machine properly, but not too expensive (I'm not rich unfortunately), what would you recommend, brand and power wise? Would they list the specifications of power units on manufacturer websites?

Also on a possibly related note: When I boot up my pc with this power supply and graphics card, my monitor has no signal for about 20 seconds or so, then finally the bios beeps and posts. With my old graphics card and power supply it would post pretty much instantly after turning the power on.
 
Yes, that is a piece of crap power supply. If you can take it back, and get your $$ back, do so.

I'm not sure where you're shopping from, but look for brands, such as corsair, seasonic, PC Power & cooling, Antec, and OCZ.

Here's a trusted source:
The card requires you to have a 450 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 35~40 Amps available on the +12 volts rails.
http://www.guru3d.com/article/his-radeon-hd-5670-iceq-review/5
 

Destyre

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Well I'll probably be buying from Amazon or ebay. I've had a look and seen a nice looking power supply which is within my budget from "Atrix". It is 720w, dual 12v rails. It doesn't seem to say how many amps the rails use though unfortunately :/
 

Destyre

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Nevermind, I read that it only works with Pentium motherboards anyway. Seen some Antec ones and Cooler master, which you suggested, they seem reasonably priced too. I just wish these voltage specs and total available power etc were posted in the description.

With regards to my booting problem with this graphics card, is that caused by the PSU also?
 

Destyre

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Would just like to note that my Corsair GS600 arrived, have been gaming with my new graphics card and this power supply for a few days without a single problem. Thanks a bunch for the help!