4K at 120Hz: How can I enable on a Sony A80K and RTX 2080 Super?

Cannibal Corpse

Cannibal Corpse

[H]ard|Gawd
Joined
Sep 22, 2002
Messages
1,277
Hello all,
I just setup my brand new Sony XBR A80K using a certified 4K-120Hz HDMI cable to my RTX 2080 super HDMI connector (normal sized connector, not the mini ones), but I can not go higher than 60Hz.
The input on the TV is HDMI 3 which has support for 120Hz (eARC). It has an additional 4K-120Hz connector (HDMI 4), and I have even tried that with no luck.

Please help!
 
I don't think the 2XXX series did 120Hz on HDMI...only DP.

Maybe if you force 4:2:2, no HDR, and 8-bit color it might work with a custom profile. I think it's a limit of the HDMI 2.0 spec on the 2XXX series. I might be wrong though.

Edit: It looks like Nvidia had some whiz bang wizardry in one of their driver updates (that theoretically shouldn't be possible due to the bandwidth limitation). Probably a driver setting that just caps the things I noted earlier.
 
Last edited:
Cannibal Corpse said:
OK, if I use a DP cable along with a DisplayPort to HDMI adapter, would that work?
Click to expand...

I don't know that the adapter would handle the bandwidth either. Might depend on the quality of the adapter (HDMI 2.1? ). Might be able to trick the GPU into allowing it with a DP cable and adapter.

I edited the above post. Look for a setting in the driver or try a custom profile.
 
You need an Hdmi 2.1 card to do this. The 2xxx series can't. You need a 3 or 4 series to make it work
 
I know this is basic, but did you set it up for 120Hz in the Windows control panel? Not that I have ever forgotten about that...
 
OK, I did it through Windows 10 display settings and I was able to choose 120Hz, I am not sure how I missed this step! nVIDIA control panel actually threw me off. OK, I know this is a limited 120Hz, according to this:

https://www.reddit.com/r/techsuppor..._2080_super_displaying_4k_120hz_through_hdmi/

"Just some FYI's regarding your setup. It is indeed possible to do 4K@120Hz via HDMI2.0 on RTX2xxx series cards - The features you're missing out by not having HDMI2.1 are: full 4:4:4/RGB colour, 10bit depth and HDR. Your HDMI2.1 cable isn't actually necessary in your current setup, because your GPU doesn't support HDMI2.1. The reason you're able to get the bare-bones 4K@120Hz is because it just barely scrape inside the bandwidth allowance of HDMI2.0 (18Gbps), without the previously mentioned extras (colour, bit and HDR)."
 
Last edited:
Cannibal Corpse said:
OK, I did it through Windows 10 display settings and I was able to choose 120Hz, I am not sure how I missed this step! nVIDIA control panel actually threw me off. OK, I know this is a limited 120Hz, according to this:

https://www.reddit.com/r/techsuppor..._2080_super_displaying_4k_120hz_through_hdmi/

"Just some FYI's regarding your setup. It is indeed possible to do 4K@120Hz via HDMI2.0 on RTX2xxx series cards - The features you're missing out by not having HDMI2.1 are: full 4:4:4/RGB colour, 10bit depth and HDR. Your HDMI2.1 cable isn't actually necessary in your current setup, because your GPU doesn't support HDMI2.1. The reason you're able to get the bare-bones 4K@120Hz is because it just barely scrape inside the bandwidth allowance of HDMI2.0 (18Gbps), without the previously mentioned extras (colour, bit and HDR)."
Click to expand...
You won't have full rgb chroma, and no vrr, without an Hdmi 2.1 card.
 
GoldenTiger said:
You won't have full rgb chroma, and no vrr, without an Hdmi 2.1 card.
Click to expand...
I am aware of that, but this will do for now, until I do the upgrade. How come on the Reddit post, it mentions that the user does not even an HDMI 2.1 cable for 120Hz? I am using an $80 4K-120Hz for that matter.
 
Cannibal Corpse said:
I am aware of that, but this will do for now, until I do the upgrade. How come on the Reddit post, it mentions that the user does not even an HDMI 2.1 cable for 120Hz? I am using an $80 4K-120Hz for that matter.
Click to expand...
That's because you're only using Hdmi 2.0 bandwidth. The cable has no benefit with your current setup :).
 
Cannibal Corpse said:
OK, I did it through Windows 10 display settings and I was able to choose 120Hz, I am not sure how I missed this step! nVIDIA control panel actually threw me off. OK, I know this is a limited 120Hz, according to this:

https://www.reddit.com/r/techsuppor..._2080_super_displaying_4k_120hz_through_hdmi/

"Just some FYI's regarding your setup. It is indeed possible to do 4K@120Hz via HDMI2.0 on RTX2xxx series cards - The features you're missing out by not having HDMI2.1 are: full 4:4:4/RGB colour, 10bit depth and HDR. Your HDMI2.1 cable isn't actually necessary in your current setup, because your GPU doesn't support HDMI2.1. The reason you're able to get the bare-bones 4K@120Hz is because it just barely scrape inside the bandwidth allowance of HDMI2.0 (18Gbps), without the previously mentioned extras (colour, bit and HDR)."
Click to expand...
The actual bandwidth limit for data is 14.4 Gbps. Full RGB 4K 120 Hz requires 22.25 Gbps. 120 Hz at that resolution requires 4:2:0 chroma subsampling to fit over HDMI 2.0b.
 
So the bottom line is that to get the 'full' features of 120Hz, I need to upgrade my RTX 2080 to 3 or 4 series, right?
 
RTX 2xxx cards can usually do 4K120 via 4:2:0 chroma, no HDR. The TV also has to be capable of it.
 
Cannibal Corpse said:
So the bottom line is that to get the 'full' features of 120Hz, I need to upgrade my RTX 2080 to 3 or 4 series, right?
Click to expand...
If you want full RGB color with HDR support at that refresh rate, then yes.
Cannibal Corpse said:
I know! I will surly return it!
Thanks for the linkl!
Click to expand...
For future reference, you just want to look for the Ultra High Speed label from the HDMI foundation. Scanning the QR code on the label should bring up the exact make and model of the cable that the label is on.

https://hdmi.org/spec21sub/ultrahighspeedcable
1666637832579.png

1666637850958.png


Generally, following the list of HDMI adopters and founders will never lead you astray.

https://hdmi.org/adopter/adoptersaffiliates
https://hdmi.org/adopter/founders
 
You must log in or register to reply here.
Back
Top