Rig shutting down all of a sudden?

[Sherkel]

I just installed a 5850. When I started poclbm on GUIminer, it worked fine for about a minute, but then the computer completely shut off. I didn't overclock the GPU at all; all I did was downclock the memory and set the fan to 100% (because I've heard it's good practice.) I started it up again without changing any settings, and started the miner again, only to have the computer shut off again, but within a few seconds of starting the miner. Any ideas on how to prevent this from happening?

EDIT: The flags were -v -128.

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[Kluge]

I'd check PSU first. What's it rated @?

[Sherkel]

Sorry, I'm not quite sure what a PSU rating is, but it's 550 Watts. Is that enough info?

[Kluge]

Sorry, I'm not quite sure what a PSU rating is, but it's 550 Watts. Is that enough info?

May be problem with gfx card drivers... but seems like a h/w issue presenting itself when stressed. Gfx card may be defective if you're confident it isn't the PSU. You may want to check out the temps, too. Many cards automatically shut off or fail @ ~95*C.

[jake262144]

Do you think you could read the make and model of that PSU?
With that information, we could put the advertised wattage into perspective.

From what you are saying it really sounds like the PSU just shutting off on you.

A failing card would most likely just hang, perhaps hanging the whole PC but it would not power it off.

[jjiimm_64]

also,  who said that running the fan at 100% is good...  good for the guy that is going to sell you another card maybe.

[worldinacoin]

Try to use cgminer where you can see the temp easily, I had the same problem with guiminer but I used the catalyst center to tune the temperature.  Have switched since to cgminer which is easier for tuning.

[Kluge]

also,  who said that running the fan at 100% is good...  good for the guy that is going to sell you another card maybe.

Generally good idea to keep card as cool as possible for longest lifespan. Fans are cheap to replace and if fan fails, the card will soon shut off, likely without damage. I've had 7 5850s running 100% w/ fan @ 100% since last April, no problem. Heat will also reduce PSU efficiency in some cases, and max wattage output.

[sveetsnelda]

Certainly sounds like the PSU to me...

[DeathAndTaxes]

If you are getting no BSOD, no display corruption (sparklies), no system instabilities just mining along and the system powers off it usually is the PSU.

I second the request for model and brand of PSU.  The gross wattage is a nearly useless spec.  What we are interested in the 12V amperage and how it is divided up.

[chungenhung]

i am almost certain it has to be the PSU.

[Sherkel]

Yeah, somehow I misread what the PSU wattage was. Thanks everyone for trying to help.