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.

[userwbrXUTWQZR]

Thanks for following up and updating this thread

I just got my 3080 and am looking into getting a screen to accompany it, and the Q80T/Q90T was one of my candidates (the LG C9 or CX being the other)

It's advertised to support HDMI 2.1 at 4k120Hz 4:4:4 (+ VRR) but by the looks of things, it's a real hit and miss, and even if it's a hit, it's unstable

Here's to hoping everything gets resolved since the screen does look nice otherwise

[psychrage]

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@userwbrXUTWQZR wrote:

Thanks for following up and updating this thread

I just got my 3080 and am looking into getting a screen to accompany it, and the Q80T/Q90T was one of my candidates (the LG C9 or CX being the other)

It's advertised to support HDMI 2.1 at 4k120Hz 4:4:4 (+ VRR) but by the looks of things, it's a real hit and miss, and even if it's a hit, it's unstable

Here's to hoping everything gets resolved since the screen does look nice otherwise

---

LG Is having similar issues. But they're out in front of it admitting the issues and working on firmware fixes. Believe they put out a firmware already, that has lessened the issues, but full fix is expected in November. This from what LG owners have mentioned on Reddit.

As a frustrated Q90T owner that Samsung essentially told to go away, and outside of my return window, I'm going to suggest you strongly consider the LG route.

[Alex_OTB]

Same issue here with a 55" Q95T and a Nvidia 3090:

Turning on "Input Signal Plus" results into no signal when using the HDMI 2.1 (port 4) source.

I've tried with an optical hdmi cable. I've just ordered a more "regular" cable which will be delivered on Saturday but I highly doubt it will make any difference.

I'll keep you posted.

Would you want to buy a Samsung 2020 Qled for a next-gen console or graphic card; I would strongly advise to wait for this issue to be hopefully solved or buy an LG Oled set.

[99xexp]

Been 2 weeks and yeah, have not yet seen any noticeable changes for me as well.

I wish they would at least put out some kind of an announcement or acknowledgement so that users can decide for themselves before purchasing an expensive TV such as the qled's.

This is quite unfortunate, but I'll be keeping my eyes open for other updates...lol TV isn't going anywhere.

[user5GBbqByhPv]

I would like to confirm that I received my rtx 3080 today and my signal is 4k 120 frames with VRR (freesync) & HDR without any problems at all on  my Q80T , my hdmi 2.1 cable is Ugreen. Software: 1402

[99xexp]

@user5GBbqByhPv Nice to hear that you got it working.

We've tested that cable and ran into the same issue. Some users reported stable operation for a few days and then inevitably getting the flickering/artifacting again with different cables.

Granted, a few users also have reported flawless workings without much hassle, but the consensus points to a rather undesirable outcome for the majority of us unfortunately.

Hope you can update us in a few days if you don't mind, and hope it stays that way for you.

Cheers!

[user5GBbqByhPv]

Sure, will update my post after couple of days. Thanks 

[psychrage]

Could i get a link to where others are discussing this?

[psychrage]

So i shared a link yesterday regarding faulty hdmi 2.1 controller chips produced by Panasonic and used on many of this years AVR's and /probably/ Samsung TV's. Samsung admins removed my post on account of violating community guidelines. Apparently outside links need step by step directions on how to fix things. Nice censorship on your broken products Samsung.

[userQ1zu5lCx7x]

I don't even get flickering with the HDMI 2.1 port.  I just get no sginal if I enable Input Signal Plus or Game Mode with a 3080.  I can only get 4k60@ 4:2:0 chroma, 8 bit thorugh the HDMI 2.1 port.  This is worse than my Samsung from 2015.  I've tried many 48 Gbps HDMI cables.  Amazon is giving me until January to return this TV luckily but please just fix it Samsung because it's absolutely beautiful in every other mode.