How much data rate does smartlink consume?

An interesting question Lars! I think SmartLink itself is irrelevant as it is only an authorisation tool. It is the data the radio consumes that matters. I do not use SmartLink and have until recently been using SoftEther VPN which was working well until a few months ago when glitches became more frequent. So I changed to ZeroTier which is great and during that change I took measurements.

Running the radio with the same settings as if I was at home consumed 1.2GB an hour approximately. It did vary 700MB - 1.5GB, depending on type of operating. However I have cut that in half by changing Panadapter FPS set to minimum + Waterfall rate set to minimum.

DAX - seems to be the major user of data. I am using a remote desktop tool on the local PC, to avoid using the remote link, to connect for digital modes. This will give you a much more reliable experience, less data consumption and trouble free communications on FT8.

I suspect every one will have their own very different data consumption figures but anyway something to compare with what you found.

Connections via SmartLink use compressed data I believe. That might make a difference to consumption. It will be important to see further replies, perhaps from Mike and also others who do use SmartLink.