Question Ryzen 7 7700x unstable PBO undervolting issue even at -10 CO

[thedard555]

I've upgraded my PC two days ago.
The temps were pretty high and reading online the 7700x seems to target 95 degrees no matter what (while stress testing/benchmarking), so I followed some guides and played with the thermal limits and PBO Curve Optimizer in the BIOS.

As far as I know i was able to set PBO to 80 Level 20 (80degrees thermal limit with -20 on the voltage curve) and it kept nice clock speeds with much lower thermals and even better benchmark results.
Now, I remember leaving AIDA64 stresstest on for like 7-8 minutes without issues.
Then I played some more but it got unstable, so I got back to the (80c -20 co) and now it won't test for more than 2 minutes without rebooting all together, I tried AIDA64 and singlecore OCCD tests with lots and lots of errors.

I'm now at the point which I can get a stable stresstest (1 hour) only with stock Curves, not even -10.
Why was it working before then? Did I get so unlucky with the chip that I can't even try undervolting?
I'm pretty new at this but the whole PBO/CO seems pretty straight forward, am I doing something Wrong?

FULL SPECS:
_Ryzen 7 7700x
_Gigabyte 4070 Gaming
_Gigabyte B650 Aorus Elte AX V2
_CORSAIR VENGEANCE DDR5 32GB (2x16GB) DDR5 6000MHz CL30
_some old CoolerMaster 650W (I'm getting a new Corsair 750w in the mail tomorrow)
_ARCTIC Liquid Freezer III 360

Could the PSU be the problem? (it's the only non new part)
Also because of the old PSU I got only 8 out of the 12 CPU_PWR cable connected, I'm fixing that tomorrow

 

[Misgar]

The temps were pretty high and reading online the 7700x seems to target 95 degrees no matter what

Don't worry about it. My 7950X has been running with all 16 cores at 86 to 90°C max. for the last
8 hours on a video render. I haven't invoked PBO or any undervolting. Just left it at stock.

When running stress tests, all cores sit at 95°C. Fine to check stability but otherwise pointless.

 

[bikemanI7]

When I originally received my NEW Ryzen 7 7700X based Desktop, i did try Curve Optimizer first week, and then it kept crashing.

Did manage to get it stable again and left it alone

Temps usually only hit 90 Occasionally on Air Cooling in my Lian Li Lan Cool 216 ARGB case

So whatever i'm doing seems to be working well

Games like Battlefield 2042, Need For Speed Hot Pursuit Remastered, Forza Horizon 5 usually only hit around 85C

So think i myself all good