System shuts down under heavy CPU load

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1

I need help diagnosing a problem that has only recently appeared with my system.  My computer will shut down under heavy CPU load, running Prime 95 and Folding@Home (CPU folding) will both shut my system down under 10 minutes.  I even had my computer shut down rendering out a video the other day.  Anything that puts more than a 60-70% load on my CPU for more than five minutes causes it to shut down.  Casually browsing the web, schoolwork and even gaming won't cause this problem, only folding/ P95 and video work.

I have an AMD FX-8350 and a Gigabyte 990FXA-UD3 motherboard, the 8350 is overclocked to 4.4GHz... I added +.25 manually to the CPU voltage.  Adding more than +.25 @ 4.4GHz results in unacceptable temps.  Cool N' Quiet is disabled and turbo boost is disabled (to prevent CPU throttling).  High Performance Computing Mode (HPC) is enabled.  This is a recent problem.  I used to be able to run my 8350, full- bore for hours and that was when I had it at 4.5GHz, I backed it down to 4.4GHz for better temps.  I also ran P95 @ 4.4Ghz a few months ago and it was perfectly stable.  It has only recently become unstable (my whole system is under a year old, about 8 months)

Yes, I have a decent PSU, its an HX750, more than adequate for an 8350 and a GTX 770.

I know that the Gigabyte 990FXA-UD3 Rev. 3 motherboards have had some VRM issues, but I have not experienced any problems with my system up until this point.  I am running Memtest now, will update on the results but so far theres no memory errors.

I can run my GTX 770 full- bore for hours doing Kombustor or GPU folding and the systems fine.  The instability is completely CPU related.  The UD3 has an 8+2 power phase design, so a 4.4Ghz stable overclock should be more than achievable, and advertises AMD 8- series CPU compatibility on the box.

Forgot to mention my CPU cooler is a Phanteks TC12DX.  I do not want to decrease my CPU freq. below 4.4.  Also, what is an acceptable max temp. for the FX-8350? AMD doesn't list it and there are a billion answers on the web, ranging from 62 C to 76+ C.

Thank you for any help that you can provide.

2

990fx-ud3 rev. 3 has fatal vrm problems. I think you can tighten it down and that will fix the problem so that's probably worth a shot.  

3

It's really unfortunate this board has the problems that it does.  When I bought it it had great reviews, but a bunch of people started complaining about the VRM issues AFTER I bought it.  I dropped $140 on it and I quite honestly don't have the money to replace it for at least another year.

4

Have the same board with a 8350 black @ 4.5 with no problems what so ever. 20c idle and 55 under load.

5

I do know that the recent versions are fixed.  Perhaps look into an RMA or something?

6

From what I have been reading, they won't replace it with a Rev. 4, only with an identical board (Rev. 3) which is the one with all of the problems.

7

Are you positive that it's a Revision 3 board? Only the Rev. 3 boards appear to have the problem.

8

sound like you can either A) get a new mobo... B) lower the frequency... 

9

Not being able to maintain a simple 4.4Ghz over clock is pretty ridiculous if you ask me.

10

Yes they will replace it with  a rev 4.0 since rev 3 is no longer available and they are not manufacturing them anymore,why would they keep manufacturing and old problematic motherboard?

11

I agree.... which is why I've never recommended a gigabyte mobo in my career in IT... I bought one years ago, installed it, it fried a CPU... never been back...

at some point, if you don't have the money to replace it.... you have to decide if it's worth having a stable PC to go beneath your overclock "threshold" (which really, overclocking isn't practically improving your experience ALL THAT MUCH...

You can try increasing the voltage... most CPUs can overclock to 4.4-4.5 at 1.4v... max temp is 62c... 56-57 is what I'd recommend running at... you might also doublecheck what temp monitor you're using.... as I've seen some pretty massive variation in temp monitors on AMD CPUs

12

I bumped the voltage up to +.050 and it has stopped shutting off.  The temps running P95 are uncomfortably high, but folding and video rendering the temp hits about 58 C max, and that seems safe to me.  P95 introduces a load that no productivity or game would introduce to the CPU, so I am fine with that.  Still don't know why all of a sudden +.025 on the VRAM was no longer sufficient for stability... it has been up until this point.

13

Companies stock up on models in anticipation of replacement.  For example, I got my iPhone 5 replaced a few days ago at the Apple store because of battery issues.  They no longer actively manufacture the 5 (replaced by the 5S and 5C) but they have a bunch of extras in the event people need a replacement. The guy at the store told me they get sent a bunch of old phone models from Apple to store in the back in case some one gets a warranty replacement. From what I am reading, Gigabyte does the same thing, just obviously not on the same scale as Apple.

14

prime 95 is not realy great anymore, do some Aida64 tests.

58 degrees is totaly fine, for rendering. you only have dual 120mm cpu fan cooler. lets say your ambient temp is arround 23 degrees.

15

With the failure rate of the previous revs I doubt gigabyte still has any rev 3.0 board