HDMI 2.1 AVR 4K 120Hz G-Sync compatible?

[dude_045]

Hi there, I'm new here on this forum. I recently, like 3 days ago, got my new LG CX55PUA. I really like this display, since I'm a PC gamer I really appreciate it's features. 4K, 120hz, HDR, Dolby Vision, G-Sync compatible, 1 ms gray-to-gray, low input latency, VRR, HDMI 2.1, etc. My problem is that I have a nice little 7.1 surround sound setup paired to a Denon AVR S720W and a bit like I was expected not all the features seems to work altogether. The thing is that I cannot connect my PC via hdmi to the receiver and have a 120hz with g-sync, I must connect directly the PC into the display. It works at a 120hz but not G-sync so there's a lot of tearing and I obviously don't want to use V-sync cause the low input latency and vrr on this tv would be a waste. For right now I plan on using a Toslink cable to connect my pc to my denon receiver, which is a downgrade cause I won't have dolby atmos enabled and I'm not quite sure if I will get 7.1 compatible. I think Toslink is 5.1 compatible, I may be wrong about that. I also doesn't seem to be able to get HDR while using "PC" resolution(see picture), HDR works only if I choose "Ultra HD/HD/SD" resolution. This is in the Nvidia control panel. When the PC is connected to the AVR through HDMI the max resolution in "PC" resolution is 1024X768. So the thing I would like to know is if an AVR with hdmi 2.1 at 4k 120hz (which I think doesn't exist yet) would work with all the features I was previously talking about (4K, HDR, G-Sync, Dolby atmos) when connected through the AVR? Any ideas or suggestions?

 

[mechman]

Can't you use the ARC HDMI port for your audio? Rather than using a Toslink cable?

I would think that the HDR question is a video card setup issue. But don't quote me on that as I have zero exposure to what you are trying to do. But I do have a lot of exposure to LG OLEDs and if they are sent an HDR signal, they will display an HDR signal. I have no idea why you wouldn't be able to get it at PC resolutions other than maybe the display won't allow it? Why wouldn't you want it to be at 4K resolution?

 

[dude_045]

Can't you use the ARC HDMI port for your audio? Rather than using a Toslink cable?

I would think that the HDR question is a video card setup issue. But don't quote me on that as I have zero exposure to what you are trying to do. But I do have a lot of exposure to LG OLEDs and if they are sent an HDR signal, they will display an HDR signal. I have no idea why you wouldn't be able to get it at PC resolutions other than maybe the display won't allow it? Why wouldn't you want it to be at 4K resolution?

Thanks for your reply. I was asking my father this evening about my issue. He said the same thing about the ARC. So we tried that and almost got it to work. The PC is connected via hdmi cable to hdmi 1 on the tv (which is not arc). Then the tv hdmi 2 (which is ARC) is connected to the amp out (which is the only port labeled ARC). So I selected TV audio as input on the avr and selected HDMI ARC as Audio out on the tv (see image 0) and it worked for stereo at first. But Dolby atmos didn't, I had to play with the settings until it asked if I wanted to reenable something. And then Atmos worked, But I haven't found a way yet to be able to use g-sync and hdr at the same time.

 

[mechman]

I can't help you with the g-sync/HDR problem - out of my realm. If I run across something I'll let you know though.

 

[Gabor Kiss]

Hello dude-045,

What kind of GPU do you have? Please check this article:

nvidia.com/en-us/geforce/news/g-sync-compatible-2019-lg-tv-available-now/

Here you find a guide for setup and below in the Comments they mention: "You need a 16 or 20 series card. GeForce RTX or GeForce GTX 16-Series GPU" for G-Sync.

I have an LG B9 OLED and a GTX 1070Ti connected to it by a standard (non ARC) HDMI port. D. Atmos + 4K + HDR + 120Hz works perfectly but not G-Sync, the card is not capable to do.