Odd 7970 behavior (throttling)

[JCviggen]

One of my 7970s has developed a rather annoying trait, after a few hours it will drop to 1/2 to 1/3rd the normal hash rate. If I open up MSI AB, move the "power target" slider and hit apply the hash rate will go back to normal for a few hours. Doesn't matter if it's at +1%, +10% or +25%, after a while the card will throttle again. This is at 62C core temp at 0.98V undervolted by the way. Not like it matters, it does the same at any speed and voltage. The other cards in the same rig keep hashing on just fine without needing the power target reset.

It's a non-ref Sapphire card (blue PCB) anyone ever had something like this?

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[kuusj98]

Have this problem with 2 HD7850's and a Cooler Master 620W PS, if I OC the cards one throttles becouse the PS can't deliver the power needed (~400W, PS has not gotten cool air for a year, so it kinda got "broken")
I advise you to take a look at your PS...

[JCviggen]

Have this problem with 2 HD7850's and a Cooler Master 620W PS, if I OC the cards one throttles becouse the PS can't deliver the power needed (~400W, PS has not gotten cool air for a year, so it kinda got "broken")
I advise you to take a look at your PS...

Thanks...PSU is 850W though and i'm well below that with 3 cards. Also this is on a PSU with a single 12V rail and the other cards are happy.

[Janmix]

Add --gpu-engine xxxx   (xxxx being GPU MHZ)  to cgminer so it can constantly use that frequency. Mine also varied a lot in gpu utilization but after adding that line it worked great.

[firefly4322]

Try making sure your drivers are upto date.  Mine was doing that for a while then I updated the BIOS and it runs like a champ now.