Nvidia Ampere and LG OLED C9 issue

VincentHanna · 11 Dec 2020 at 20:05

Managed to get hold on an Nvidia 3070 whilst waiting for my 3090 to arrive.

I have LG OLED Firmware 05.00.10 and the latest Nvidia 460.79 driver

1) I no longer have the option of YCbCr422 under the Nvidia control panel 'change resolution' menu. I only have 420, 444 or RGB. What's going on there? I didn't have this issue with my 2080ti

2) ~~I supposedly have a HDMI 2.1 cable connected directly from the GPU to the TV, and yet 60hz is the maximum refresh rate I can select. Surely it should now allow me to select 120hz?~~

Edit - I solved this issue by selecting from the 'PC' resolutions, instead of 'Ultra HD, HD, SD'

3) If I turn G-sync on there is a flicker on the screen unless I use YCbCr420

Are other people having these issues?

VincentHanna · 12 Dec 2020 at 10:35

Participant · 12 Dec 2020 at 11:12

@VincentHanna I have exactly the same as point 2 with my 1650 Super connected to my LG OLED CX.

I'm struggling with the other points but have you enabled HDMI deep colour and game response mode in the LG's settings for the HDMI ports you're using?

I found I had issues with HDR enabled in Windows until I enabled both of these.

Also - and I haven't confirmed that this makes any difference - I read a few Reddit posts etc. saying to define the HDMI port as PC or console in the LG home hub (or whatever it's called) settings.

Poneros · 12 Dec 2020 at 11:17

I think it's due to it being HDMI 2.1, I have the same issue on my RX 6800 where there's only 420, 444 & RGB (full/limited) as options. Also, afaik once HDR gets engaged it's all 420 10bit regardless, so even if you have it at let's say RGB 12bit all it would do is it would down-convert back into 420 10bit, so you might still get some benefit, but it's not like if it were native. Obviously the exception would be dolby vision but it's not in the game (yet?).

smogsy · 12 Dec 2020 at 11:28

@VincentHanna I have exactly the same as point 2 with my 1650 Super connected to my LG OLED CX.

I'm struggling with the other points but have you enabled HDMI deep colour and game response mode in the LG's settings for the HDMI ports you're using?

I found I had issues with HDR enabled in Windows until I enabled both of these.

Also - and I haven't confirmed that this makes any difference - I read a few Reddit posts etc. saying to define the HDMI port as PC or console in the LG home hub (or whatever it's called) settings.

all fine here on 460.79 with 3090 + LG CX 48

Gsync is enabled 4K 120hz is active no flicker with full RGB and HDR on

what i have done & just worked
instant response (on) switches on auto with gsync anyway
turn game mode on as picture setting
tell port its PC in LG software
deep color on

no issues no flickers on hdmi - product code on the rain forest: B07WN8C7XV

make sure you have the latest firmware on the CX 3.11.30 fixed flickering in release notes

Radox-0 · 12 Dec 2020 at 12:31

I have a LG C9 and RTX 3090 (though multiple RTX 3090s and 3080FEs and all bhavaiour similar) using same drivers and firmware on both TV and GPU.

First of all, I do have an odd quirk in that I get signal not displayed sometimes and a reboot solves issue, saw another thread with RTX 3090 and C9 combo so think may be handhake issue going on.

However once in Windows everything is fine. 120hz @ 4k, G-Sync, HDR 4:4:4 12bit / 12bit and eARC to Atmos all fine.

As others suggested, HDMI deep colour is the important one to enable. Enabling this will also enable instant game response anyways. For specific answers

1) I no longer have the option of YCbCr422 under the Nvidia control panel 'change resolution' menu. I only have 420, 444 or RGB. What's going on there? I didn't have this issue with my 2080ti

Amusingly I do not see YCbCr422 when running G-sync and 4K @ 120hz either. However this is a non-issue given you can see 444 which is the better option to pick all things being equal. Its what I have selected with mine at 12bit (I know LG C9 cannot display 12 bit, but recall vincent Teho's video where when you get option go 12 bit he believes)

3) If I turn G-sync on there is a flicker on the screen unless I use YCbCr420
No issue in that regards with RGB or 4:4:4, I suspect it may be your cable. My main HDMI 2.1 cable works perfect. I got a free one rated apparently rated at HDMI 2.1 more recently and that does flicker.

Smogsy suggested one, I use one with code: B08CS79VZN as I needed one with 5 meter length.

I would suggest changing HDMI cable in your shoes first. While I have not used a 3070, I have 3080 and 3090s and cannot imagine the 3070 with the same HDMI 2.1 port having any issues.

VincentHanna · 13 Dec 2020 at 10:50

smogsy said:
all fine here on 460.79 with 3090 + LG CX 48

Gsync is enabled 4K 120hz is active no flicker with full RGB and HDR on

what i have done & just worked
instant response (on) switches on auto with gsync anyway
turn game mode on as picture setting
tell port its PC in LG software
deep color on

no issues no flickers on hdmi - product code on the rain forest: B07WN8C7XV

make sure you have the latest firmware on the CX 3.11.30 fixed flickering in release notes

Radox-0 said:
I have a LG C9 and RTX 3090 (though multiple RTX 3090s and 3080FEs and all bhavaiour similar) using same drivers and firmware on both TV and GPU.

First of all, I do have an odd quirk in that I get signal not displayed sometimes and a reboot solves issue, saw another thread with RTX 3090 and C9 combo so think may be handhake issue going on.

However once in Windows everything is fine. 120hz @ 4k, G-Sync, HDR 4:4:4 12bit / 12bit and eARC to Atmos all fine.

As others suggested, HDMI deep colour is the important one to enable. Enabling this will also enable instant game response anyways. For specific answers

1) I no longer have the option of YCbCr422 under the Nvidia control panel 'change resolution' menu. I only have 420, 444 or RGB. What's going on there? I didn't have this issue with my 2080ti

Amusingly I do not see YCbCr422 when running G-sync and 4K @ 120hz either. However this is a non-issue given you can see 444 which is the better option to pick all things being equal. Its what I have selected with mine at 12bit (I know LG C9 cannot display 12 bit, but recall vincent Teho's video where when you get option go 12 bit he believes)

3) If I turn G-sync on there is a flicker on the screen unless I use YCbCr420
No issue in that regards with RGB or 4:4:4, I suspect it may be your cable. My main HDMI 2.1 cable works perfect. I got a free one rated apparently rated at HDMI 2.1 more recently and that does flicker.

Smogsy suggested one, I use one with code: B08CS79VZN as I needed one with 5 meter length.

I would suggest changing HDMI cable in your shoes first. While I have not used a 3070, I have 3080 and 3090s and cannot imagine the 3070 with the same HDMI 2.1 port having any issues.

Thanks to you both

I searched Amazon for B07WN8C7XV as @smogsy suggested, and then selected the 3m version which is B083TZ2Y3Y. It arrived today and I just hooked it up

And yet the problem remains!

Deep Colour has been enabled on my C9 HDMI port since I got it.

The flicker only goes away if I turn G-sync off, but I want to use G-sync in Cyberpunk 2077.

VincentHanna · 13 Dec 2020 at 11:29

UPDATE

I swapped the HDMI port I was using on the LG C9 from HDMI 1 (Which was set to 'PC' under the HDMI options) to HDMI 4 (which my Xbox One X used to use, before I sold it) and there's no flicker now.

Yay

But also

?

smogsy · 13 Dec 2020 at 11:52

maybe there not all hdmi 2.1? funny enough im al using port 4

Radox-0 · 13 Dec 2020 at 11:52

VincentHanna said:
UPDATE

I swapped the HDMI port I was using on the LG C9 from HDMI 1 (Which was set to 'PC' under the HDMI options) to HDMI 4 (which my Xbox One X used to use, before I sold it) and there's no flicker now.

Yay

But also

?

Oh yeah that happened to me ages ago. Should have mentioned it

posted it in C9 thread, for some reason had issues in hdmi one, moved to port 3 and problems gone. Odd thing is, out of curiosity since I did a factory reset along with firmware update on my tv recently trying to solve the issue where I on occasions get signal not detected with my 3090 for a min or so, tried HDMI port 1 and it works fine again. So many bizarre quirks at times.

Radox-0 · 13 Dec 2020 at 11:53

smogsy said:
maybe there not all hdmi 2.1? funny enough im al using port 4

they are on the C9, all are full 48 Gbps, but seem to be fair share of bugs it seems.

HRL · 13 Dec 2020 at 12:03

Yep, 4 x HDMI 2.1.

Weirdly, I heard that this years model, the CX, is limited to 40Gbps though. No idea why!

Been watching this thread as I have a C9 and am awaiting a 3090FE myself.

Ghuraba · 13 Dec 2020 at 21:05

When you say black screen flicker do you mean the screen signal goes and you get a black screen for a second or two then the screen returns with the instant game response logo? This is happening to me on LG C9 with 3070. I am using a Ugreen HDMI cable but have just ordered a TRUE HQ hdmi cable to see if it is the cable or not. With there being no official certified cables actually available to buy it is hard to rule out it being the cables many are using.

VincentHanna · 13 Dec 2020 at 23:53

No, it was more like tiny glitching on the screen, rather than a black screen.

VincentHanna · 15 Dec 2020 at 17:08

New issue today - Anyone using eARC on the C9?

Installed an ASUS ROG Strix OC 3090 and set the output to 7.1 in Windows 10, then ran the sound test. All the sounds play, but they are only coming from either the left or right front speakers.

What the hell's going on now?

LukieBoy007 · 14 Jan 2021 at 12:25

Ghuraba said:
When you say black screen flicker do you mean the screen signal goes and you get a black screen for a second or two then the screen returns with the instant game response logo? This is happening to me on LG C9 with 3070. I am using a Ugreen HDMI cable but have just ordered a TRUE HQ hdmi cable to see if it is the cable or not. With there being no official certified cables actually available to buy it is hard to rule out it being the cables many are using.

Did you sort this in the end? Just found this thread and having exactly same issue. Really irritating.

morta · 14 Jan 2021 at 12:35

im a little confused..im still on my 1080ti wast i wait for my 3080..i have the LG CX. currently under UHD 4k 60hz. but if i select 3840x2160 under pc...it allows me to enable 120hz...i thought this was only possible to do with an HDMI 2.1 connection though.

Radox-0 · 14 Jan 2021 at 12:43

morta said:
im a little confused..im still on my 1080ti wast i wait for my 3080..i have the LG CX. currently under UHD 4k 60hz. but if i select 3840x2160 under pc...it allows me to enable 120hz...i thought this was only possible to do with an HDMI 2.1 connection though.

AFAIK HDMI 2.0b can do 4k @ 120hz, however it would be at 4:2:0 and at 8-bit I suspect your seeing. 10-bit, 4:4:4 etc will not be selectable.

LukieBoy007 said:
Did you sort this in the end? Just found this thread and having exactly same issue. Really irritating.

only way you will sort it is by disabling instant game mode, but that also disables VRR. Some people do that and just stay in game mode which gives all low input lag but no VRR. However while annoying, normally once in game, never an issue here.

LukieBoy007 · 14 Jan 2021 at 12:45

Radox-0 said:
AFAIK HDMI 2.0b can do 4k @ 120hz, however it would be at 4:2:0 and at 8-bit I suspect your seeing. 10-bit, 4:4:4 etc will not be selectable.

only way you will sort it is by disabling instant game mode, but that also disables VRR. Some people do that and just stay in game mode which gives all low input lag but no VRR. However while annoying, normally once in game, never an issue here.

So basically with my 3060ti I can output 4k 120Hz 10bit HDR, but have to turn off Gsync?

Radox-0 · 14 Jan 2021 at 12:49

LukieBoy007 said:
So basically with my 3060ti I can output 4k 120Hz 10bit HDR, but have to turn off Gsync?

yes if you want to get rid of that instant game message to pop up. Disable instant game mode but leave "ultra HDMI deep black" on and stay in game mode. Personally I live with message flickering for those few seconds and prefer G-Sync available.