TLDR: I have a 3090 Strix that I think is busted. Unfortunately, it 'works' until you start gaming. Then 5 to 20 minutes later or even less, I get black screen reboot. I have swapped a lot of components and I'm pretty sure it's the GPU.
It is water cooled, and I don't think I have thermal pads of appropriate sizes to replace the stock cooler. Has anyone RMA'd a GPU in this condition before? Any experiences?