Original topic:

Q90T 4K 120hz RTX 3080 Black screen

(Topic created on: 1/4/21 8:03 AM)
userWr4Dj6yMsj
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Hello, i have read the other posts about flicker issues with Q80T-Q90T on 4K 120hz with a RTX 3000 series but in my case when i switch my resolution to PC 3840 x 2160 on the hdmi input 4 that supposedly supports hdmi 2.1 4k 120hz the screen turns completely black with some white lines , when i choose the ultra hd 4k x 2k 60 hz it works normally. My cables are club3d 8k that is certified hdmi 2.1 and the PS5 cable , my TV firmware is 1460.9 and nvidia driver is the 460.89.

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userPE9ugsfWb4
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It sounds like the fault is your cable, club3d 8k is only rated to support speeds up to 32,4 Gbps. 

I know club3d 8k advertised the cable as a hdmi 2.1 compatible. In theory this cable should work but from experience you will lose the signal. My club3d 8k is only stable at 2560x1440@120Hz chroma YCbCr442. You really need a full 48Gbps bandwidth cable to achieve a resolution of 3840x2160@120Hz.

 

Try SIKAI Optical Fiber 8K 48Gbps-Ethernet hdmi 2.1 cable this is a good alternative. I can run this cable at 4096x2160@120H without signal loss on my Q90R.

 

 

 

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userWr4Dj6yMsj
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I  don't think so the club3d cable i have is certified for 4k 120hz from hdmi.org and i also tried with the PS5 cable that is capable for 4k 120hz but neither worked and as i mentioned if it was a cable problem like other people i would see a picture with flickering not compete black screen with white lines.

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userKA3u6cIiXs
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what is best 4096x2160 or 3840 x 2160 ???

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The3rdDimension
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Exact same problem, backscreen and later no signal on Q80t with RTX 3070 on the 4th HDMI port using a certified HDMI 2.1 cable (verified using HDMI Licensing Administrator app)

No official response from Samsung, LG fixed problems with their HDMI 2.1 long ago.

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userWr4Dj6yMsj
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I got it to work when i completely disabled gsync , so the problem is the VRR support i guess we need to wait for a fix from Samsung.

userPE9ugsfWb4
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Everything would have been so much easier if Samsung had made a TV version with a display port and full support for Nvidia G-sync ultimate, like the Nvidia BFGDs concept.

 

@SamsungAl  A premium high end TV with g-sync ultimate and freesync 2 would sell faster than ever.

 

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CJx
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Exactly this. Enabling VRR on 120hx at 4k appears to introduce handshaking and stability issues between GPU and screen. I have played at 4k120 with VRR for an hour or more and then it will just stop working all of a sudden. It's very finicky and the only real solution so far is to disable VRR for 4k120.
Hopefully there is both and/or Nvidia drivers and Samsung firmware that adresses this.

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user79HehVWarb
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There are major issues with 1460.9 firmware and RTX 3080 when using port 4 (HDMI 2.1).

I've found people who have the RTX 3080 working with this set, only to find out that they are still on firmware 1403. I know no one on 1460.9 that has a working set.

 

In my experience, if I use a high quality cable, I get no signal when engaging Input Signal Plus

If I use a lower quality cable, I can get a signal but it blacks out every so often. (Opposite of what you would think).

 

So, I wouldn't go out and buy any new cables until Samsung has fixed this with a firmware update. I have the Club3D certified cable too.

 

On a technical note, if I hack the EDID in Windows 10 via CRU, I can get everything to (mostly) work. I have to drop the link bandwidth to 32Gbit and remove all DSC support. Even with this hack, if I change modes to an HDMI 2.0 mode, then I have problems, and engaging GSync can cause similar problems.

 

Hopefully next week we see an update.

useriphYVNPw02
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Not sure if this helps, but when I would boot up I would constantly get "No signal" screens while also using an RTX 3080 on HDMI Port 4. While not a full on solution, I would always set the input signal to HDMI 4 > Turn off the TV > Turn on the PC and wait about 10-15 seconds to boot to login page > Turn on the TV > 9 times out of 10 I will get a normal picture on the TV. While not convenient in any way, I found that this has been the best workaround for me to solve "No signal" messages. Maybe try doing this and see if it works for you? 

I also do get 4K on HDMI Port 4 at 120hz, games like Cyberpunk 2077 and Metro Exodus look stunning on it with a 3080. 

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