The Windows operating system does not support ASIO drivers.
Lets put an easy example and then work towards your setup.
Imagine, the RME card would be your only recording/audio card in your system.
Then you could work in your DAW program without any issue by loading the RME ASIO driver.
In contrast to that Windows OS and typical Windows applications are not able to access the recording interface,
as they do not support ASIO, so they need a Windows compatible driver (-> in this case a WDM driver).
For this you need to create a WDM device in the RME driver settings and if you select the speaker device you get a speaker symbol in the Windows sound settings, to make it easier to identify the port where the speakers are connected to.
This device you configure in Windows Sound as the default sound device.
Then Windows OS and applications like Firefox (for youtube etc) can access the FF800 through the windows compatible WDM driver.
Similar situation, but now you have two audio interfaces:
- RME FF 800 and
- the nVidia Sound device
What device to choose now ?
I assume that you do not want to plug your monitors between FF800 and nVidia card depending on whether you are recording or not, so lets assume you have therefore your monitors connected to the FF800.
The rest is simple. If your monitors are connected to the FF800, then you need to create WDM devices for the analog I/O port of the FF800 where the monitors are connected to.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14