GPU drops utilization after 2-3 mins of gameplay

Hey guys,

unfortunately I ran into a really troublesome problem.
***EDIT*** Fixed for now, by installing an even older driver (347.88)...

Symptoms
As the title reads, my 680M drops utilization to around 30-70% after several minutes of any game.
It starts to load fine, it stays at 99% utilization for a bit but then drops, and the framerate goes down with it. Clocks stay the same, heat is no issue (around 65-70°C).

This is all at stock clocks, so no overclock of any sort. Just SVL7's vbios that runs the card at 758 Mhz stock (which I flashed 2 years ago and never had an issue).

I even tried 3Dmark11, the first run-through after booting my notebook is fine and results in a GPU score of 6200. But at the second run-through the utilization drops in the GPU tests, it seems like the card couldn't handle the load or something, and results in a GPU score of 4700.

Please note that this is not a CPU bottleneck, as it is the case with so many other "GPU utilization" problems.
My i7 980 runs just fine and passed all the benchmarks with the same score as when I bought the notebook, also Intel's stresstest.

I noticed this in every game (and 3Dmark11) I tried to fire up: Witcher 3, Far Cry 3, BFBC2, Sleeping Dogs, Crysis, all GPU intense games which all ran flawlessly at 99% utilization.

What I tried so far
I rolled back the driver (358.91 WHQL to 353.62 WHQL), no change.
I re-installed Windows 10 (completely new, not just a restore point). No change.
I flashed a slightly overvolted vbios (as I thought the card couldn't handle the load, maybe it would help), 1000 instead of 99xx. No change.

Now I am the end of my road, as I fear the possibility that the card itself just might be dying.
What else could I do, to rule out a hardware failure?

 

Hate to suggest it because I'm suspecting hardware fault at this stage, but can you get your hands on the stock vBIOS and test against that?

 

Thanks, I will try that. I immediately used SVL7's vbios because my stock vbios sucked, didn't even allow me to overclock with MSI Afterburner.

 

Alright, so I tried the stock rom, didn't change the drop in utilization. However, I also tried 3 older drivers, and it seems this utilization bug is introduced in the 35X.XX series. I am running 347.88 now, and it doesn't drop... need to test a longer period to verfiy this though.

Thanks for your reply!