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Drivers & Software

Adept II

Signal corruption over HDMI


I have an AMD Radeon RX Vega 64 Liquid. The original ones from AMD when they came out.

Desktop PC, one PC monitor on DisplayPort, and one TV nearby connected via HDMI cable, on which I occasionally  play movies from my PC.

I have experienced this issue from Day 1, but never bothered posting before just now, as the workaround is fairly easy. But now it gets annoying, and I'd like people's input in case someone knows a solution or has more clues I could follow.

So, basically the problem is that I see signal corruption over HDMI on the TV when turning the TV back on after it was turned off., and corruption only goes away if I unplug then re-plug the HDMI cable (either the TV end or the PC end, it doesn't matter, as long as I unplug then re-plug).

It doesn't always happen, but almost always (I'd say at least 90-95% of the time). Even happens if the TV was turned off for only a few seconds, then when turning back on the signal isn't stable, despite the fact that before turning off I could have watched movies for hours with no issue whatsoever. It doesn't need the TV to be off for a long time for the problem to issue, and obviously, the HDMI connection is secure and I'm not touching it at all before the issue occurs.

Not sure the signal "corruption" is the right word,l but don't know how else to call this. Here's a video of the issue if it can help:

Obligatory specs:

Motherboard = ASUS Zenith Extreme
Chipset = X399
BIOS = version 2001
CPU = AMD Ryzen Threadripper 1950X
GPU = AMD RX Vega 64 liquid cooling edition
RAM = TeamGroup 32 GB (4 x 8 GB)
PSU = Corsair HX 1000
Monitor = Acer XR341CK, connected via DisplayPort
TV = LG OLED55C7P, connected via HDMI

OS = Windows 10 Pro x64 build 1903
AMD Chipset driver version installed =
AMD GPU driver version installed = 19.8.2

P.S. some of tghe things I've tried:

1) Reverting to stock clock and voltage (I usually run undervolt/underclock). But stock voltage/clock didn't change anything and I'm still seeing the problem.

2) Setting a lower resolution on the TV: 1920x1080 instead of 4K. No change.

3) Setting refresh rate to 30 Hz instead of 60 Hz on to TV. No change.

4) Trying an HDMI signal extender. Didn't help.

5) Trying different HDMI cables (tried 4 of them, of different lengths between 4' and 15')

4 Replies

Updating firmware of the TV may solve the problem. You can also try getting support from AMD.
Online Service Request | AMD 

Adept II

Thanks. I should have mentioned that the TV's firmware is the most recent version. And I have observed the same behavior on all versions that I've had since I bought the TV (around 2 years ago).

Honestly, my suspicion is that the HDMI port on my card is defective, perhaps does not supply enough power?


If there was a problem with the HDMI port, I think you couldn't get any images or get any healthy images. If you ask this question to AMD, I think they may tell you what the problem is. If you try to turn the TV on when play a game, and you experience the same problem, there is no problem about GPU clock speeds, I think.

Note: In some cases, core clock speeds (or VRAM speed) change when second monitor is connected to some systems. This may cause mouse lag or display corruption in some systems. When AMD releases new drivers, they write what has been fixed. This kind of problems are fixed sometimes.

Adept II

Wow. Took me forever, but I finally figured out the culprit once and for all. I have been troubleshooting this issue for years, and turns out I was looking in the wrong place: Windows, GPU hardware and driver, HDMI cables.

The issue is my TV itself.

It is the LG OLED TV setting to enable "Ultra HD Deep color" on the HDMI input.

If I turn that off, I'm not getting the problem anymore.

I've tested it long enough to be sure of it now, and am even able to produce the issue pretty much on demand when turning the setting on, and make the problem go away when turning it off, all the while keeping the TV open.

The drawback is turning Ultra HD Deep Color off makes it not possible to use 4:4:4 full RGB output on my TV from the AMD driver (only 4:2:0 is then available), but I'm willing to accept that if it fixes that pesky problem. (The blacks look a lot more black with UItra HD Deep color off too, that was also something else that was bothering me, blacks levels were too light for me).

So happy now

Edit: spelling, typos.