13700K Degraded in Minutes?

[Graptik]

I upgraded to a 13700KF about a week ago and have been tweaking my overclock of it ever since. I got it stable at 5.5GHz all P-Cores with E-Cores disabled. I also overclocked my RAM from 3600MHz CL16 to 3900MHz CL17.
This configuration was rock solid stable, passing hours of Cinebench, Y-Cruncher, TestMem5, Realbench.
Everything was going fine until I decided to see if I could get my RAM stable at CL16 with 1.45V. I managed to get this stable but then the next day, I started to get blue screens on Windows.
It has gotten to the point now where I can only get the system stable at 5.1GHz all core, even opening applications at anything above this will cause the system to crash. I have clean installed Windows twice but the issue persists.
The weird thing is that the RAM does not seem to be affected at all, I'm still using my 3900MHz CL17 overclock and even the CL16 1.45V overclock is still stable, it is only the core ratio that is affected.
I'm wondering if using 1.45V on the RAM has degraded the CPU, even though it was only using that voltage for a day. That is the only explanation I can think of as to why there has been such a massive drop in the capabilities of the CPU.
This is extremely frustrating and any help is appreciated.

Specs:
CPU: i7 13700KF
RAM: Kingston Fury Renegade 32GB 3600MHz CL16
GPU: EVGA 2080ti FTW 3 Ultra
PSU: Corsair 750 RM750X
Cooler: Noctua NH-D15S

 

[Graptik]

What were your SA and VDDQ voltages?

VDDQ was left on auto which is 1.2 and SA was 1.13. My motherboard actually gives a lot of voltage (1.4V!!) to System Agent on Auto for some reason, but I put it at 1.13 and it was stable.

 

[Graptik]

And what were your Vcore voltages for the overclock and what motherboard?

CPU Vcore was at 1.28. Motherboard is MSI Z790 Pro-A. I've found out that it's not even stable at stock now. Resetting everything to optimized defaults in the bios, it won't even run 5 minutes of cinebench without giving an error. Something has definitely gone wrong, just not sure whether it's the motherboard or the CPU.

 

[Graptik]

Doubt it was stable to begin with since you didnt stress test it properly

I absolutely did test it properly. As I stated in the OP, it ran hours of Y-Cruncher, Prime, Cinebench, TestMem5 and Realbench, now it won't run 5 minutes of Cinebench at stock.