System switches off randomly?

mcchase

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Hi guys!

About 6 months ago i built my first computer and i have had no real trouble with it until very recently. For the last couple of days now it has had an odd (and very annoying habit) in which the system switches off with absolutely no warning at all and generally refuses to start again for more than a couple of minutes if i don't leave it alone for a while. As far as i can tell there is absolutely no correlation between when it switches off and what program is being used or how hard the system is being worked. Initially i assumed it was the PSU as its a Tagan TG480-U01 which i understand is pushed quite hard for my set up, however the case fans (connected through molex) remain spinning when the system shuts off! My system has always run pretty hot (CPU 44c on idol, 58c pushed) so im hoping the constant heat hasn't broken something :( ! My set up is as follows,

- coolermaster 330 elite case
- HD 4870 graphics card
- phenom 955 processor
- samsung F3 1tb harddrive
- ASUS M4A78T-E motherboard
- Cheap generic 1333 DDR3 memory
- Tagan TG480-U01

Really hoping theres nothing massive wrong and any advice would be really, really appreciated! Thanks in advance,

Miles.
 

mcchase

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I was running XP pro (x86) until about a month ago, now im on 7 pro (x64). I really couldn't put a time on how long it takes to shut down, some times 30 minutes sometimes 8 hours.
 

mcchase

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Thanks, any idea what a good course of action would be from here?
 
That definitely SOUNDS like a heat problem. Any time the computer shuts off and doesn't try to reboot, heat is instantly a suspect.

Doubly so since your system was running hot already. And a triple red flag because you have a 4870, which is known for generating a lot of heat.

And a quadruple red flag because it looks like your motherboard has the first PCIe x16 slot seated very close to the CPU area. So it's quite possible that a larger card like that will block the air coming in from your case fans, which means not much cool air will be getting to the CPU. So that area will be stagnating and heating up into a nice little hellbox.

My guesses for fixing it, starting with the easiest and cheapest:

1) Reseat the CPU, removing the current thermal compound, and apply Arctic Silver instead. (cost: [strike]free[/strike] whoops, about 7 bucks)

2) Move your graphics card from the top PCIe x16 slot to the bottom PCIe x16 slot. You should get a lot better airflow. But check the manual and/or e-mail the manufacturer to make sure performance won't be affected; occasionally, the lower slot will only operate at x8. But you'll most likely be OK. (cost: free)

3) Replace the rear (exhaust) case fan with a more powerful one to improve airflow. (cost: probably no more than $15)

4) Get a new CPU fan/heatsink. If your current one is dying, that could be causing heat issues. And also, if you're using the original CPU heatsink/fan that came with it out of the box, those are known for being crappy. You'll get a lot better results out of a third-party cooler. Zalman is known for making great CPU coolers, but also known for being so massive they don't fit in a lot of cases. If you can get one, great; if not, even a mid-range cooler like this http://www.newegg.com/Product/Product.aspx?Item=N82E16835426002 should do a lot better than what came with it. (cost: $30-$75)

5) Get a new case with an intake fan basically right above the CPU area (cost: $50-$100, and a pain in the ass to move everything). Alternatively, you could try using some plastic fins or tubing to divert the air from your existing case fan to blow directly at the CPU area.

6) Go to water cooling. This would be almost a desperation move, because there really has got to be at least one way out of the five above to lower the temperature more easily.
 

mcchase

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Thanks very much for the comprehensive advice :) ! I have tried to make my case as cool as possible with scythe kama 120mm fans front and back an 80mm side fan and a turbine exhaust fan for the graphics card but prehaps the stock cooler just isn't good enough! I have placed an order for a Scythe Mugen II and if that doesnt help i will try and patch in heat "shields" to direct airflow in the right way. Again thanks very much for your help.
 

mcchase

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Hey, really need some help now. Writing on my PS3 under Linux because the re-starting problem has got so bad it doesn't even have time to boot up anymore. Obviously something has broken, i removed the graphics card and replaced the PSU and am still getting the problem. I'm probably grabbing at loose straws here but is there anything anyone can suggest i try before inevitably give up and take it to a repair shop? Again many thanks in advance.
 

Shappo

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Well if it's a new build, I wouldn't take it to a repair shop.
Your best option is to identify the component that isn't working, then send it back to the manufacturer.

Try these first for help you find the problem:
*Get the latest drivers for all your hardware off the internet (some CD's are outdated, like graphics cards)
*Reseat everything (RAM, CPU, PCI Cards)
 

mcchase

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Thanks for the reply again, I've already re-seated the RAM and GPU, I havn't re-seated the CPU because i havn't got any thermal paste lying around. but i've heard the system wouldn't boot at all if it was a CPU problem? Either way, thanks for you're imput i guess i'll just keep trying to narrow it down.
 
Well, go get some thermal paste; that's what I'd recommend. If the heatsink isn't making good contact with the CPU anymore, that can cause it to overheat REALLY quickly. Seems especially likely if the system was running hot already.

You may also try testing the RAM in another system if you can, or at least try them one at a time in your current system and see if it turns on that way. If one or more sticks are going bad, that can cause all manner of problems.
 

mcchase

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Speedfan doesn't record any values that are extremely hot? But if you recommend it, I will try and get hold of some thermal paste today and re-seat the CPU today. As for RAM i only have one stick and I have tried it in a different DIMM slot but not in another computer, I will also try and get that covered today if I get time. Thanks again for the help!