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.

[psychrage]

I've tried every nvidia driver I could find since the 30x0 cards dropped.
I don't know if its coincidence, but after turning on the TV last night, I got a new flicker pattern I hadn't seen with any other driver. Regardless, handshaking/flicker issues as a whole still exists.

[empythreedom]

Felt I would stop in and mention that I purchased this tv tonight and have it in this configuration:

• 55" Q90T upgraded to 1402 firmware
• Gigabyte Gaming OC 3080 using 456.71 drivers
• IBRA 2.1 HDMI Cable 8K Ultra High-Speed 48Gbps Lead (10 foot)
• Configured to Port 4 PC Mode, set to game mode
• Nvidia control panel: PC Mode, 3840x2160, 120Hz, 32-bit, RGB, 10bpc, Full, Gsync enabled (not validated)
• Windows Display settings, Play HDR games and apps set to on
• When switching sources, it shows Freesync(VRR) 120hz Input Signal Plus HDR UHD
• Pendulum demo works (set to 40-120hz)
• Chroma "the quick brown fox" entirely legible
• Black set to low does do black crush under testing, set to auto - ok
• UFO test blur busters works - ok
• UFO test frameskipping checks out - ok
• UFO test ghosting - evidence of pixel overdrive

There is no flicker, no disconnects what so ever.  I'm about to test out Watchdogs Legion in HDR.  Have fun everybody, I'm glad I didn't let the fear in this thread turn me off of this TV.

[99xexp]

@empythreedom 

Good to hear an update from a new owner!

There are plethora of good reasons to pick Q90T alongside with the 4k@120hz capability so fear it may be, the thread wasn't created for that purpose. We had numerous owners test (including myself and few of my buddies) prior to this thread's creation, and came to a conclusion that it wasn't an isolated issue. Others joined in this thread with an interest to purchase a Q90T in the near future and were disappointed, but the intentions are to report based on user-based issues and to assist in pinpointing the root cause (efforts at least).

I kindly ask to keep members updated if you don't mind (or care), as we have also seen a few users reporting in issues days after a stable connection. Better of course, is if it stays working!

[userR02ujNatz7]

Hi all,

Just a heads up on my experience, I own a Q80T 65 inch and a 3080 Founders edition. I bought in advance the Ibra 4k HDMI 2.1 cable, so had everything ready to try out 4k 120hz HDR goodness...

This then only lead to a disaster of me questioning whether I had a broken GPU. As soon as I turn on the "input signal plus" on HDMI 4, I'm left with a glitching mess of a screen (flashing black screen, and picture distortion). I have personally tried 3 different "supposed" HDMI 2.1 cables now, and all of them have the same problem. Personally I think that all these so called 2.1 cables are just fake advertising. My guess is we need to wait for the new consoles to be released to get some official 2.1 cables.

I get the best results from a standard 4k HDMI 2.0 cable (I'm guessing that came with my PS4 pro). This cable has a perfect picture, and runs flawlessly with the Nvidia settings at 4k 120hz RGB 10bpc Full. However after maybe an hour or so, the screen will flicker black. Once it starts it will flash the black screen every few minutes, and gradually happen every few seconds until the picture is no longer picked up and you have to remove and reconnect the HDMI cable. This is as close to working as I can get.

I spoke to Samsung to raise my concerns, to which I have been told from management that there is a compatibility issue with the TV and the RTX 30 series GPUs. They advised they have no firmware updates lined up to fix the issue, but they are clearly aware of the problem.

So the only hardware that has actually got HDMI 2.1 compatibility, is not compatible with Samsung's TV that is supposedly HDMI 2.1 compatible...

If the issue is still there when the new consoles are released, they will have huge complaints coming in. As many will have purchased these TVs specifically for the HDMI 2.1.

I have raised a complaint with Samsung at this stage as mis-selling, if they don't fix it then I have been mis-sold. However they didn't get management to call me back as they promised, so it all looks like a s*** show at this point.

[psychrage]

It's been a few days. Can you give an update?

I had(and still have as it gives me the least issues) a UGREEN cable that worked perfectly for 2 days.

Also you can turn on and off the Q90T with no problems getting image back?

It generally works as long as I turn on the TV before my computer, or turn on the tv before waking the display after a minimum of 5mins. Otherwise I have to cycle Input Signal Plus On-Off-On to get picture back.

[empythreedom]

So, I use it as a secondary monitor, the primary is on displayport. So far there are rare situations where it forgets the pc connection, its difficult to put together what conditions have caused that. It happened once, the first time, after I was using the youtube app on the tv and my computer went to sleep. I set the TV to PC before waking the computer and it attempted to repair the connection. Curiously NVIDIA control panel still recognized the connection but the TV did not and I had to disconnect the cable. The act of reconnecting seems to set to a default, duplicate PC connection, where the settings are 4k60. I had disabled HDMI-CEC for a while to observe its impact but I've turned it back on to use EARC. I have not seen the problem today.

[psychrage]

Instead of pysically reconnecting the cable, you can just cycle input signal plus.

[useryop2lhdtIz]

Replying to the thread instead of to my three-week-old post for better visibility, heh.

Reporting back in after three weeks of testing the method of uninstalling my monitor driver. Been running at 4K120 + HDR, Game Mode disabled the whole time, and no flickers or lost signal. I still had to cycle Input Signal Plus off and on before switching to HDMI 4, though, to get the picture to show.

However, with GeForce driver 457.09, I noticed I don't have to cycle the Input Signal Plus setting to change to HDMI 4, no matter how long my TV's been off. Interesting. I enabled Game Mode today and tested a little with it, and I found no issues. I even enabled G-Sync from the NVIDIA Control Panel, and everything seems to be working okay so far. I will keep this thread updated with my progress.

Note that I am still using that Zeskit ultra high speed HDMI cable you can find on Amazon. Maybe something in this driver is helping. Another thing to note, though, is that I also replaced my CPU on 31 Oct, going from an Intel Core i5-7600 to an AMD Ryzen 7 3700X. Not sure if that should make this much of a difference.

[useryop2lhdtIz]

Reporting back in after three weeks of testing the method of uninstalling my monitor driver. Been running at 4K120 + HDR, Game Mode disabled the whole time, and no flickers or lost signal. I still had to cycle Input Signal Plus off and on before switching to HDMI 4, though, to get the picture to show.

However, with GeForce driver 457.09, I noticed I don't have to cycle the Input Signal Plus setting to change to HDMI 4, no matter how long my TV's been off. Interesting. I enabled Game Mode today and tested a little with it, and I found no issues. I even enabled G-Sync from the NVIDIA Control Panel, and everything seems to be working okay so far. I will keep this thread updated with my progress.

Note that I am still using that Zeskit ultra high speed HDMI cable you can find on Amazon. Maybe something in this driver is helping. Another thing to note, though, is that I also replaced my CPU on 31 Oct, going from an Intel Core i5-7600 to an AMD Ryzen 7 3700X. Not sure if that should make this much of a difference.

[userZX93pu5U7J]

Hi. For me, the main issue is bright flickering when running 120 Hz + VRR (G-Sync compatible) on all resolutions (4K, 1440, 1080). HDR doesn't matter, flickering occure without HDR too. Did you notice something simillar? It is especially visible on lighter scenes and picutres, but it happens on darker too.

[userFO1OJGwZjh]

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@userZX93pu5U7J wrote:

Hi. For me, the main issue is bright flickering when running 120 Hz + VRR (G-Sync compatible) on all resolutions (4K, 1440, 1080). HDR doesn't matter, flickering occure without HDR too. Did you notice something simillar? It is especially visible on lighter scenes and picutres, but it happens on darker too.

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I am facing the same issue as well.

VRR is not working properly, I get bright flickering, 1080p. 1440p, 4k, I set refresh game to 4k 60 (in a game) but it did not fix the problem either.