NVIDIA
In order to use an NVIDIA GPU for hardware encoding you must do the follow
Get your GPU ID
Go to Settings > NVIDIA Driver
Here mine is "GPU-7f326d12-d4c8-4011-9db1-36c47710daf6"
Switch to Advanced View
Add Extra Parameter
Under "Extra Parameters" insert
--runtime=nvidia
Add New Variable
Add a custom variable by clicking "Add another Path, Port, Variable, Label or Device"
Config Type: Variable
Name: NVIDIA_VISIBLE_DEVICES
Key: NVIDIA_VISIBLE_DEVICES
Value: [YOUR GPU UID, EG GPU-7f326d12-d4c8-4011-9db1-36c47710daf6]
Click save and apply your changes.