I recently purchased a LG OLED C2 TV, which supports 4k120Hz but only has HDMI 2.1 ports. I am aware of HDMI 2.1 being an issue on AMD, even though my GPU is Nvidia (RTX 3060Ti) I want to switch to AMD in the future, so I opted to invest in an AMD-friendly setup. I purchased the Cable Matters active DisplayPort -> HDMI 2.1 converter mentioned in this Reddit thread, which purportedly can do 4k120. However, when I change it from the default 4k60 modeline to 4k120, the TV shows a “no signal” message. In fact, to get 120Hz I need to drop the resolution down to 1440p.
Even though I’m not going for VRR (yet), I also tried flashing the VRR-enabled “Spyder” firmware just in case it fixes the refresh rate (it does not). I tested every DP port on the 3060Ti as well, with no changes. What might I be doing wrong?
In that reddit thread, they dont seem all too happy about that converter either, lots of people mention that it doesnt work correctly for them, so maybe your exact setup just isnt compatible with it?
My understanding is that it doesn’t have VRR for people (at least without the special firmware, which indeed only works for some). Not seen anything about it not supporting 4k@120Hz, though maybe I missed it as I read so many different threads about this topic…
What adapter are you using specifically, because on their website I can only find 4k30.
I bought this one: https://www.amazon.de/-/en/gp/product/B094XR43M5
Can you elaborate on why HDMI 2.1 is supposed to be problematic on AMD?
HDMI Forum blocking the implementation of HDMI 2.1 in open source drivers. Really sucks for people who want to use their systems connected to TVs.
I have a LG CX and a AMD 6900XT. I just settled on some random noname adapter cable since i never could find reliable enough information on the net regarding VRR(irc you need atleast a rx7000 series amd card for that). Everything works on my setup except VRR. Atleast on the CX remote you can press the green button seven times to get an overlay that shows if 10bit, vrr, hdr, chroma subsampling, etc is in place. Helped me a lot when i tried to dial in everything.
Like 4k120 HDR VRR is perfectly possible with hdmi 2.0 bandwith. It will just be subsampled down to horrible 4:2:0…Wow, I had no idea about the green button info, thanks! I am not too bothered about VRR (it seems totally broken on Wayland for my GPU at the moment anyways, and I have been fine without it so far), but I bought this TV for the 120Hz and good colors, which so far have been mutually exclusive :P
