Did you check whether your .nvidia-settings-rc file is corrupted, e.g… delete/rename it, see if it gets recreated.
You’re using a pre-Pascal syntax, see:
https://forums.developer.nvidia.com/t/solved-nvidia-settings-a-gpu-1-gpumemorytransferrateoffset-3-2000-doesnt-take-effect/178021/2?u=generix