Hard reset of my PC whenever I try to use LDSR upscaling - What's going on

[cmp-nct]

Very rarely my PC switches off when I have a high workload on the GPU, but with LDSR it's consistently and reproduceable.
I upgraded my PSU from 850W to 1050W (Enermax), it was pointless.
My GPU is a Nvidia 3090

So what happens is that I click on upscale (just anything 2x upscale) usind LDSR and as soon as the model starts working the PC is hard-reset. I can hear an audible short 'click', it was louder with the 850W and is a bit softer with the new 1050W PSU.
Sometimes it takes longer to start up and the red LED on the 3090 is flashing, usually it's just a reset.

The GPU works to produce images for 10 hours in a row (getting quite warm in the process) but one single LDSR run and I get the reset.
So there is no event, it's not a software crash as it really goes down instantly.

My only guess was that it might be the PSU getting barely overloaded on one of the 3 PCIe lanes, so I bought a new one. Sadly this did not help.

Anyone has experienced something like this ?
Anyone an idea what this might be ?

[cmp-nct]

After weeks and months of reboots, and a new PSU I found the reason today.
I had to change 12V rails on the PSU (even the 1050W one).
Now I supply it from a CPU+PCIe rail AND a dedicated PCIe rail and the problem is gone.

According to GPUz it draws 420W, which is a bit below a single rail spec but I suppose that GPUz does not see the real peaks.
The PSU supplies no more than 480W of power on a 12V rail.

So anyone with a 3090 or 4090 should keep that in mind and make sure to look the specification of your PSU up so you can provide power from TWO different high-amp rails.

[sempai0000]

Excuse me, friend, I have the same problem but I don't understand much about electronics. Could you give me a more detailed explanation of how you solved your problem with restarts when doing upscale?es decir mi pc se apaga en cuanto intento hacer un upscale,

[cmp-nct]

Get a single rail power-supply with plenty of Watt spare.
Or read up your current one and find out if it is multi-rail, then connect the GPU from two different rails.

Ensure your drivers are up to date, you can also try using MSI Afterburner or similar tools to reduce the max power on your GPU, that might stop it from crashing but also hurts performance of course.