I think the Deck's AMD GPU is part of an APU, so CPU and GPU on one chip. That probably helps thermals a bunch. Also, I wonder how much the decision to use AMD was influenced by terrible Nvidia drivers on Linux
I would wager the terrible Nvidia drivers were a big factor. I personally won't buy another Nvidia card unless they make sweeping changes (like open sourcing it completely. Their open source announcement earlier is a good step but not far enough to win me back). I do wish the AMD pro driver were open source though.
