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Lost 4k120hz resolution on 456.71 or later with LG C9 and Club3d cac-1085
03-14-2021, 01:55 AM (Last edited: 03-14-2021, 03:01 AM by dan1)
Post: #1
Lost 4k120hz resolution on 456.71 or later with LG C9 and Club3d cac-1085
Hi Guys,

Lost 4k120hz resolution on 456.71 or later nvidia drivers.

I have

2080ti - can only output 4k120 through dp1.4
LG C9 - can do 4k120 10 bit
Club 3d CAC-1085 - converts dp1.4 to hdmi2.1

Seems like a few of us using the cac-1085 dp1.4 to hdmi2.1 adapter are all stuck on old nvidia drivers, because the newer ones don't allow 4k120hz 10/12 bit


Maybe something to do with DSC?

I noticed the latest CRU has lots of hdmi2.1 options now which looks great.

I thought CRU might make a difference, but not sure what settings to use or if it can fix anything.

I'm back on 456.71 now because it's all working, but would like to revisit the issue and see if it can get resolved.

I guess I would start by installing the latest nvidia drivers 461.72, then what?

Some sort of log or CRU dump? to see why the 4k120hz resolution disappeared?

I've also posted on Guru3d here https://forums.guru3d.com/threads/what-c...677/page-2

Seems a few knowledgeable people know what they are talking about

Here is an image of a fresh 461.72 install
As you can see under PC resolution - there is no 4k120hz option, and only 60hz under UHD/HD/SD resolutions, But it shows up in CRU
[Image: jdQNvrr.jpg]

Any help would be appreciated, thanks
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03-14-2021, 03:06 AM
Post: #2
RE: Lost 4k120hz resolution on 456.71 or later with LG C9 and Club3d cac-1085
It's a driver bug. It's listed as an open issue on their forum, which means they know about it and plan to fix it: "Displayport-to-HDMI 2.1 protocol converter clock limited to 600MHz pixel clock [3202060]"
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03-14-2021, 03:09 AM (Last edited: 03-14-2021, 03:12 AM by dan1)
Post: #3
RE: Lost 4k120hz resolution on 456.71 or later with LG C9 and Club3d cac-1085
Ahh thanks Toasty, I thought I might be able to get around it somehow with CRU Big Grin

I saw all your new hdmi2.1 changes to CRU and thought all those options might do something heh
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