CAC-1085 works flawlessly on my 1080TI with Samsung Q90T @ 4k/120Hz/422/10bit HDR

14 replies

Finally my adapter arrived. I was a bit anxious because of the problems others reported.

For me it works flawlessly on the theoretical maximum of the 1080TI (4k/120Hz/422/10bit HDR). Switching in/out of HDR, and changing resolutions works smoothly. Even when changing in-game.

One weird limitation: 120HZ only allows 422 colors, no matter the resolution or bit-rate. This might be a limitation of my TV, or some missing EDID in the adapter. At 60HZ, RGB/12bit  or YUV444/12bit is possible.

Because 1080TI does not have DSC, 444/12bit is not possible, this is a known limitation.

Ya.. I've been trying to mess with it too.. I actually can't do any custom res

You can do HDR 4K 120 Hz 8-bit dithered RGB on DisplayPort 1.4 without DSC by creating a custom resolution with reduced blanking. There are instructions on various forums.

I'm not able to run a custom res/refresh for some reason

net200777 wrote:

Please tell me if you can do 4k 96-98hz 10bit 444.

There is no need to run 10-bit RGB at a lower refresh rate. HDR 120 Hz 8-bit dithered RGB with a custom resolution is equal or superior to a 10-bit signal without dithering.

Weird that you have literally no problems with the adapter. I'm running my CAC-1085 with a CAC-1372 HDMI 2.1 cable, a RTX 2080Ti and a LG SM9000 (the one with 4x HDMI 2.1 sockets).

If i change resolution in the Nvidia Control Panel, the adapter loses signal and I must pull out the power cable and plug it back in to get an image up on the screen again. 

Same bug happens if i'm running any video games in Full Screen Mode.

Once my resolution is set, things are fine but if i dare try to change any settings (SDR to HDR or resolution) I get a black screen, adapter loses signal, have to turn it off and on again. 

Pressing ALT TAB while a game is running in Full Screen Mode also causes the adapter to lose signal and screen goes black. Again... had to power down the adapter and switch it back on again.

I did notice that when I ran my games in Borderless Windowed Mode, I had no problems at all changing the in-game resolutions. No black screen, no signal drops. I can even ALT TAB just fine too.

I also tried it on a C9 and got the same problems. Once again, in Borderless Windowed Mode the C9 worked fine with the adapter.

I have the same issues. Blank screens unless power cycled. Same setup except TV is LG CX 48”. Tried two different USB cables and chargers too.

I hope Club3D can solve this because the adapter works well when it actually works.

Since I created the custom resolutions, I also experienced the signal loss twice. I am not sure what triggers it, will look further into it.

I tried to reproduce the signal losses: Changing resolutions/refresh rates/colordephts in NVidia panel, and HDR in display settings: Always works fine. Changing this inside a game in fullscreen or windowed mode (Assasins creed Odyssey): Also works fine. Alt-Tab out of the game: also fine.

The only thing that causes signal loss: Alt-tab out of the game, then change refresh rate in NVidia settings. But this is very exotic, and might simply be a NVidia issue.

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