Custom Resolution Utility (CRU)

[EeK]

I recently bought an LG C9 OLED TV, after previously owning a B7 and a C8. Its main selling point is 1440p@120Hz refresh rate. I'm having some issues and was hoping that @ToastyX or anyone else would be able to help me out.

With the B7 and C8 (which only support 1080p@120Hz), I connected my PC to the receiver (a Denon AVR-X4400H) using my GPU's (1080 Ti) single HDMI out. If I do that with the C9, only 1080p is available at 120Hz, for some reason (4K@60Hz works flawlessly).

eARC is currently not working with my TV and AVR (known issue between 2017 Denon receivers and the C9), and regular ARC causes massive audio delay (also a known issue on LG OLEDs). So, the only alternative to have 1440p@120Hz video on the TV and audio coming out of the speakers connected to my AVR, was to connect the GPU directly to the TV (through HDMI), and use one of its three DisplayPort outs to connect a second HDMI cable to the AVR (using a DP to HDMI adapter).

Now, the problem. Windows sees those connections as two individual displays. I can either extend or clone the picture from the primary display (TV) to the secondary one (AVR). If I extend, I get 1440p@120Hz, but no high definition audio formats support. If I clone, I get support to all audio formats, but only 1080p@120Hz.

Is there any way to use CRU to fix that? Here are some screenshots showing what the available settings look like:

Extend:

Set up screen
Available resolutions - PC and TV
Supported audio formats

Clone:

Set up screen
Available resolutions - PC and TV
Supported audio formats