Octane render restarts whole PC mid render

[marco_py]

I'm having this new issue where my PC will just randomly restart around 10-30 frames in to a render. I'm thinking it's a power supply issue but

1: this is a very simple project which takes 15s per frame to render.
2: Last week I was working on a much heavier project and everything was fine.

I have a HX1200W PSU with an RTX 3080, max load should be around 850w with my setup, so I don't know why it's doing this.

The only thing I changed was update Windows last week, I'm on the latest Octane subscription version , 2020.1.5-R4.

The pc doesn't immediately restart when I hit render, it does it after several minutes (usually 10-15 frames).