Forza Horizon 3 limited to 30 FPS due to A/V set up

[mof]

My game is always locked to 30 FPS because of my AVR/monitor setup.

I've got an HDMI out from my graphics card to the AVR and then HDMI out from the AVR to the montior just for sound. I also have display port out from the graphics card to the monitor for the picture. (monitor only supports 4k 30 over hdmi but does 4k 60 over DP). I have to use duplicate displays - extending displays causes tearing issues.

It seems like the game is limiting to 30 FPS based on the HDMI (1.4) coming from the receiver even though I'm using the DP (1.2) signal to play the game on.

I've never had this problem with any other games (except Forza Apex come to think of it) and I'm assuming it's because it's a Windows 10 UWP.

I could get around this by either not using my speakers and just using the monitors speakers or
connecting the motherboard audio out to the receiver but I'd prefer not to have to do that.
Any suggestions?

 

[mof]

I really don't get your setup.

For instance, I have:

Titan X HDMI out - Denon AVR for audio
Titan X DP out - Asus X34a monitor

Why do you need your AVR to loop back to your monitor? The GPU carries an audio signal.

Thanks for the reply.
You're right, I don't need it go from avr to monitor for the pc but it's already plugged in for other devices where both A+V are carried through the same HDMI cable e.g games console, set top box.

I have the DP and HDMI inputs as duplicates because windows treats the AVR as a display device even though it's not and I only use it to carry audio (for pc use) and not video.

I could try unplugging the HDMI from AVR to the monitor with Forza and see if that helps.

EDIT - Unplugging the HDMI cable did work although it's not a great solution.
Also it's stuttery and horrible above 30 FPS even with the cpu affinity/priority 'fix' so I'll go back to locked @30FPS.

 

[mof]

Are you sure its not a hardlock on the game?

You mean the game is not allowing more than 30 frames @2160p?
It definitely does.