I’ve been getting a Window come up when Sonar loads:
 
“NVIDIA Virtual Audio Device (Wave Extensible) (WDM). The above Audio/MIDI device was disconnected from your system. Would you like Sonar to reroute these outputs to an available device?”
 
I answer ‘no’, and then Sonar works normally.
 
Of course this window is very annoying, but I also wonder whether this is compromising Sonar’s performance in some way?
 
My question to those more computer savvy than myself is: is it okay to delete this NVIDIA Virtual Audio Device (Wave Extensible) (WDM) from my system completely? It shows up in Device Manager, and I’m thinking of uninstalling it from there.
 
Also in Device Manager are listed 4 instances of “NVIDIA High Definition Audio” and a  “High Definition Audio Device” (no brand specified). I’m wondering if I can uninstall all these too.
 
My interface is the RME Fireface 800 and is the only Audio device I need for this computer, which is used exclusively for audio production in Sonar and Wavelab.

Right-click on them and select "Disable device" in Windows Device Manager. That should be good enough.

Thanks Scook for your response.
 
I guess my question is more pointed toward is it safe to do so, rather than how do I do it. I am reluctant to go ahead until I am sure it is not going to affect anything. 

you maybe can disable it on the BIOS-setting..

Removed as mismatched case, sorry :)
 

The NVIDIA entries are for HDMI audio.  You can disable them all in the Device Manager.  
The High Definition Audio Device is usually the PC's audio (e.g. Realtek) and is the generic Windows installed driver because you haven't installed the sound chip's hardware driver.  It can be disabled in the Device Manager too since all you use is the RME.
 
The disabling is the best option.  If not, on a reboot at some point they will come back.  
 
 

Dilaco1
Thanks Scook for your response.
 
I guess my question is more pointed toward is it safe to do so, rather than how do I do it. I am reluctant to go ahead until I am sure it is not going to affect anything. 

I disabled the HD Audio Device on my PC some time ago with no ill effect. IIRC, there are threads from a year or so ago recommending this.

Thanks everyone for helping me out.
 
I now feel safe to disable these in device manager.