2020 75" Q90T HDMI 2.1 with NVIDIA RTX 3080/3090 Flicker & Disconnects

[99xexp]

Hey everyone.

I wanted to know if anyone else is experiencing problems with achieving 4k 120hz + HDR with the new RTX graphics cards on the current Q80T/Q90T models.

With number of feedbacks from a small community on Nvidia including myself, we noticed that enabling Input Signal Plus (or so called HDMI UHD Color) in order to use VRR on Game Mode results in an unstable, flickering state and will not work properly.

As a reference, it looks something like this: https://www.youtube.com/watch?v=RBc_qmA3nx4&feature=youtu.be

We have tested rigorously through the past week trying out tens of HDMI cables (we know they're not "Certified" HDMI 2.1, but are advertised as Ultra High Speed HDMI with 48gbps output), different resolution+refresh rate settings, and with the last two known updates to Samsung TV firmware (1302, 1402.1) as well. Nvidia also released two driver updates so far however, the problem doesn't seem to resolve at all.

Interestingly, Input Signal Plus on other ports besides Port 4 (hdmi 2.1) works perfectly as they should, whether it's connected via hdmi 2.0b or hdmi 2.1 cable (limited bandwidth by the port anyways), with maximum setting of 4k60hz + HDR on 4:2:2 subsampling. The problem occurs as such in the above mentioned video ONLY when Input Signal Plus is enabled for Port 4. You cannot set the resolution higher than 4k60hz without that setting.

After numerous attempts at different cable lengths and models, PSU swaps (6pin+6pin on different source), and gathering reports from the community with verified issue on all Samsung TVs, we are inclined to believe that it's likely a firmware / support issue on Samsung QLED and its proper HDMI 2.1 support.

LG CX/C9 also had a similar issue (G-Sync related) but was followed up by their team and was resolved with a firmware update to the LG TVs.

I reached out to Samsung via Twitter but was simply told to let Nvidia know lol. Not very helpful so far.

If anyone else here have had a similar experience or resolved it on your own, we would love to hear it from you.

Thanks!

Edit 10/15/2020:

We are aware that the user manual on the TV's only list 2560x1440@120hz or 4k@60hz for VRR as officially supported resolution and refresh rate. However the issue is persistent even when VRR is disabled both either via Game Mode (TV Setting) or Nvidia Control Panel.

tl;dr Port 4 currently has issues even for hdmi 2.1 bandwidth usage.

[99xexp]

@userFO1OJGwZjh 

Well, congrats on getting it working to your TV. I think most of us are still in the dark with this with no solution as of yet.

I keep seeing posts of people about trying different cables (tens have been tried already by the community lol), disable VRR (Game Mode/G-Sync in Nvidia control panel), and other settings that have been countlessly tested but to no stable solution. The manual does state that freesync is only to 2k@120hz and/or 4k@60hz, but hdmi 2.1 for pure bandwidth should still enable 4k@120hz w/ 10-bit for HDR.

[CJx]

Did you have any blacks blown in dark areas out with VRR enabled? I'm waiting for a 3080 but currently on a 2080Ti on a Q95T when VRR is enabled you get black 'highlights' that appear in dark areas. Everything other than blacks blown out are fine though.

[userIZJMpp129T]

I come bearing news. 

Yesterday my Ibra 2.1 cable arrived.

I updated firmware to 1402.

It works 

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[userIZJMpp129T]

So the problem started happening again, and I seemed to have found a way to help it, but I would like others to try too.

Before putting the hdmi2.1 cable in, set input signal plus on. Then when it's plugged in, turn on your computer. This is working flawlessly for me. 

[useryop2lhdtIz]

Hope that solution continues working for you. My experience has been anything I've tried will appear to work for a day or two at most, and then the random splashes of color/lost signal starts up again.

Ran into something new today that might help. I'll need to see how well it works over the next few days:

I was trying to run 3DMark to see how well my new setup performs, but when I tried to run a benchmark I got an error: EnumDisplayDevicesA() failed. The solution to this error is to uninstall the TV from Monitors in Device Manager, as described here: https://support.benchmarks.ul.com/en/support/solutions/articles/44001954929-enumdisplaydevicesa-fail...

One thing they don't tell you to do is to check the "Delete the driver software for this device" checkbox if it appears. I did not do this the first time, so I still got the same error when trying to start a benchmark. Finally I checked this box this time around, and the benchmark runs.

The device listed under monitor for my Samsung Q80T appeared as "PnP Monitor (Standard)". After uninstalling and rescanning for new hardware, it became "Generic PnP Monitor". I am going to see if this helps with the random colorful splashes and other flickering as well. Currently conservatively testing at 4K @ 60 Hz + HDR, Game Mode disabled.

edit: These were the same settings I had since my post on Sunday, but last night the symptoms returned. Here's hoping the Device Manager song-and-dance above will resolve those.

[99xexp]

@useryop2lhdtIz 

@userIZJMpp129T 

Thanks guys.

My results are pretty much spot on with @useryop2lhdtIz with random splashes of color/flicker on port 4 with input signal plus.

I will try both of the suggestions for enabling input signal plus on first before pc boot and plugging the hdmi in as suggested by @userIZJMpp129T and device manager route. I'm pretty burnt out from the same results occurring no matter what settings are tried so hopefully we can come to a solution soon.

edit: If someone suggests that QLED tvs don't technically support VRR 4k@120hz as stated in the manual, note that this is an issue regardless of whether VRR is enabled or not. 

[99xexp]

@CJx I personally didn't experience any of those symptoms. I'm running 3080 FE on Q90T but have not seen anything remotely similar to your description.

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@CJx wrote:

Did you have any blacks blown in dark areas out with VRR enabled? I'm waiting for a 3080 but currently on a 2080Ti on a Q95T when VRR is enabled you get black 'highlights' that appear in dark areas. Everything other than blacks blown out are fine though.

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[psychrage]

I'm beyond irritated with this display at the moment.

I have to physically reconnect the hdmi cable multiple times a day.

The turning on the tv before PC no longer works. The signal will "degrade" over time leading to flickering and picture drop outs. Can SOMETIMES fix this by turning input signal plus off and back on. It doesn't matter if I leave it off and try 60hz. Same thing happens.
I'm not even trying to use VRR/G-Sync. I just want the 4k 120 as the tv was advertised to do.

I already had a 4k/60 display before buying this tv in August. Now I'm out of my return window and this TV just does not work as it should. Samsung doesn't seem to give a hoot.

[userc8egQRuGvt]

Ive talked to support and they try to blame Nivida.  I have a tech coming next saturday to test the "2.1" port and its banwith support. They are ignoring the problem. Ive contacted a few people i know for advice and this would fit well in a class action law suit. as more 3080s and 90s hit the market, those with these TVs will start to notice. 

[psychrage]

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@userc8egQRuGvt wrote:

Ive talked to support and they try to blame Nivida.  I have a tech coming next saturday to test the "2.1" port and its banwith support. They are ignoring the problem. Ive contacted a few people i know for advice and this would fit well in a class action law suit. as more 3080s and 90s hit the market, those with these TVs will start to notice. 

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Too bad a class action will only get us like $20 back in 6-8 years.

For what it's worth, I contacted rtings via Twitter a couple weeks ago. They're going to verify my/our issues when they get thier hands on a 30x0.

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