So, I bought an RX 7600 XT, when I was still using my 10 year old TV. Recently upgraded to an LG C4, reading the news about AMD support for HDMI 2.1 on Linux, I also went looking for a DP->HDMI adapter and found one that claims to even support VRR. After a week of getting random audio cuts, suspecting the adapter was at fault, I went pure HDMI…
To my surprise, I could run at 4K 120hz with VRR and HDR. Doesn’t that require HDMI 2.1?
You’re probably running in non-RGB 4:4:4. Quick test is to have some red console text against a gray background and if the text is fuzzy with compression artifacts at the edges, then it is not 4:4:4. You can check what mode your TV is in by clicking the green button with the two dots seven times.
Thanks for the tip. It says YCbCr420. Anything I can do to improve that?
Nope, you’re running into the dreaded AMD HDMI 2.1 limitation. The situation just sucks.
I would kindly ask the HDMI forum to point me in the direction of a DP to HDMI adapter that supports VRR or FreeSync. They seem so motivated to gain more funds from royalties, surely they know how to persuade me.
Fuck those guys. I really wish LG would support DP a bit more in their products.
The real question is though… if you haven’t noticed the TV using YCbCr420 until it was pointed out to you, why would you spend more time looking into it?
In retrospect, I have noticed. Thought it was badly compressed content.
DP to HDMI adapter that supports VRR or FreeSync.
Here you go: https://www.amazon.com/Cable-Matters-102101-BLK-Computer-Adapter/dp/B08XFSLWQF
It’s slightly quirky, but it does work. Although I don’t use HDMI audio so maybe you’re already using the same adapter.
It’s not the adapter I bought, but also seems VRR is lacking:
“VRR/G-Sync/FreeSync are not supported.”
Have you experienced otherwise?
It works, but it only works on Linux so they don’t advertise it. You may need to update the firmware to get the best experience too.