Screen tearing and graphical problems with extended display using HDMI sound out to receiver

[mof]

I wasn't sure which forum to post this in.
I have audio going from my graphics cards HDMI out to my A/V receiver. To get this to work in Windows 7 my AVR is detected as a display so I've had to extend that display even though I only have one actual monitor. My monitor is connected to the graphics card by display port (I don't use HDMI because it limits the refresh rate to 30Hz @ 2160p).

When I watch some videos online and when I play games I will get screen tearing despite v-sync being on. The image has other lines that shouldn't be there and generally doesn't look right.

As soon as I turn my AVR off and my PC goes back to just using one display, all the screen tearing and graphical errors go away and the game/video looks perfect.

Something about extending the displays is causing a problem. I noticed that the AVR was set to 2160p 30Hz so I changed it to 1080p 60Hz so that the refresh rate of both displays would be the same but that didn't help.

Is there a way of getting just audio over HDMI from a graphics card (or sound card) without having to treat it as another display device?
Maybe there is something I can change in the Nvidia control panel?
Perhaps this works better on Windows 10?

 

[mof]

Thanks for the replies. I didn't think there was a way round it.
I've read that using different types of connectors can cause tearing with extended displays (e.g HDMI and Displayport) even when the monitors are identical.
I'm hoping there will be an adapter that will let me have one cable going from the pc to the AVR carrying both audio and video @2160p 60Hz - DP 1.2 to HDMI 2.0 - but I don't know if it will be possible.
There are already HDMI 2.0 to DP 1.2 adapters which might help with the multiple displays problem.

 

[mof]

Set your card to duplicate display rather than extend desktop, then set your monitor to the primary display. This should eliminate the screen tearing on your monitor. I'm not sure where the setting is on NVidia drivers but I've had to do this on all my amd cards on every windows version since vista!.

I've just tried duplicating the display and it's working. I'm playing the Witness and the sound is working and there's problem with the picture. Thanks Jamesyboyjim.

I noticed that when I changed the source of my monitor to the HDMI input I could see the game on there too. If duplicating the display is sending out two video signals when you're playing a full screen game will it affect the performance?

EDIT: Rise of the Tomb Raider doesn't seem any different with duplicate displays. I didn't do a thorough test comparing frames per second. I'll see if I notice anything in other games.