@mcc
"GPU: 0. If you have 2 GPUs in your system, you can select which one is used to encode. This is not recommended, as NvEnc is already very efficient and the little gain you can get from using a second card is lost by having to copy the frame to the second GPU."
I'm guessing you don't have two cards with nvenc so this isn't gonna do anything
https://obsproject.com/forum/resources/nvidia-nvenc-guide.740/