Unstable GPU after system switch

[Random_Animator]

So i already tried to solve this with another post, and initially i thought i had it fixed but its returned. 

 

Backstory

I recently upgraded to a new AMD system from an old Intel one. My gpu was working perfectly fine for almost 2 years in the old system but has been crashing in my new one. Depending on how stressed the GPU is depends on how the system reacts. Small to no stress, system operates perfectly fine. 30-50% small hitches but not often, 50-80% usage makes the system stutter and can cause the display driver to crash but they recover. Above 80% usage the system will shutdown within 5 minutes, no warning just full power loss. System will only turn back on if I turn the power supply off and back on

 

What I've tried

 - Power cables, all double checked and plugged in fully and in the correct ports

 - System BIOS is up to date

 - Windows has been reinstalled

 - Ran a DDU to remove all nvidia, intel and amd drivers before reinstalling all necessary ones

 - Stress tested other components, CPU can run 100% rendering a full 3D scene for 12+ hours no problems with ram clocked to 3600

 - Putting GPU in different PCIE slot

 

At this stage i'm worried it might be hardware but want to double check before i go buying new components 

 

Old system specs

 - Intel 5820k

 - 32gb 2400 DDR4

 - RTX 2080ti

 - 750w EVGA supanova 80+ gold

 

New system specs

 - AMD 5950x

 - 64gb 3600 DDR4

 - RTX 2080ti

 - 850w EVGA supanova 80+ gold

[Random_Animator]

So turns out a SATA power cable was the tiniest bit out from fully plugged in, i feel like a dunce but at least i don't have a shot PSU or GPU