CAC-1085 and LG 48CX – Only Limited Color range after driver 456.38

Updated on 26-07-2023 in Adapters and Cables
6 on 17-02-2021

Currently I have a RTX 3090, a LG C9 65″ plugged in directly to HDMI, and two LG CX 48″ connected via CAC-1085 and using their HDMI 2.1 cables.

If I stay on driver version 456.38 I can get “Full” Output dynamic range and select “RGB” for Output Color Format. Using any other driver version and I am limited to the “limited” Output Dynamic Range and I cannot select “RGB” as the Output color format.

I’m not sure what to do at this point. Both adapters have the same problem on either TV. I’d like to use all three monitors at the same time with the latest driver revision. All TV’s are set to HDMI Ultra HD Deep Color and have all the same settings otherwise.

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0 on 17-02-2021

HI Calyton,

If you downgrade back to Nvidia’s 456.38 drives it should work again.


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3 on 28-02-2021

Hello Clayton006,

I have read on [H]ard|Forum that the last driver that works with adapter is 456.71, after that there is issue in driver. It is registered as open issue since 461.40: Displayport-to-HDMI 2.1 protocol converter clock limited to 600MHz pixel clock [3202060].

Luckily, user “kasakka” on [H]ard|Forum successfully copied/extracted necessary files from working driver to the newest driver for working adapter. It is in topic “LG 48CX” on 171th page comment #6,819.

on 28-02-2021

My mistake, “kasakka” on [H]ard|Forum only managed to get working DLSS 2.X for 456.71 driver. Therefore no new working driver for adapter.

on 01-03-2021

Thanks for all the info. I submitted a driver bug form for these adapters basically being broken after the 456.38 driver. Really stinks that I can’t use the latest drivers with these.

on 02-03-2021

Should ask if the adapter is broken or the driver of the card is not working propperly with the adapter?

I think that there is something wrong with the DSC in the drivers of nVidia or maybe even the drivers from the LG C9? Who knows, no one really does.

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