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CAC-1587 driver crashes when selecting 4k 120hz

CAC-1587 driver crashes when selecting 4k 120hz

Updated 3 days ago in USB Type C

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Suharik 6 0 5 days ago

Hello i bought CAC-1587 ( type c to hdmi 2.1 4k 120hz )
And i bought NUC 14 pro mini pc, that has CORE 3 100U intel cpu ( supports 4k 120hz ), windows 11.
It has thunderbolt 4 (USB 4) port.

My TV is LG OLED CS, has hdmi 2.1 port (with other pc i had 4k 120hz no problem )

Now once i connect CAC-1587 cable from mini pc to TV, it works with 4k 60hz, and i got option to select 120hz in display settings, but the moment i select it, the driver crashes, screen goes blank untill its back.

I updated drivers.

I found a tricky workaround, if i reduce chrome subsampling from RGB to 4:2:0 (the worst color), then 4k 120hz works, even with HDR.

4:2:0 uses less bandwith so it seems the cable has not enough bandwidth for RGB 4K 120HZ.

4:2:0 4k 120hz HDR cant be handled by HDMI 2.0, its too much bandwith too, so it seems the mini pc is capable of over 4k 60hz.

It seems the cable has more bandwith than HDMI 2.0, but not as much as advertised (48GBS)

faulty cable?

Thanks

Hello i bought CAC-1587  ( type c  to hdmi 2.1  4k 120hz ) And i bought NUC 14 pro  mini pc, that has CORE 3 100U intel cpu  ( supports 4k 120hz ), windows 11. It has thunderbolt 4 (USB 4) port. My TV is  LG OLED CS,  has hdmi 2.1 port (with other pc i had 4k 120hz no problem ) Now once i connect CAC-1587 cable from mini pc to TV,  it works with 4k 60hz, and i got option to select 120hz in display settings, but the moment i select it, the driver crashes, screen goes blank untill its back. I updated drivers. I found a tricky workaround, if i reduce chrome subsampling from RGB to  4:2:0  (the worst color),  then 4k 120hz works, even with HDR. 4:2:0 uses less bandwith so it seems the cable has not enough bandwidth for RGB 4K 120HZ. 4:2:0 4k 120hz HDR cant be handled by HDMI 2.0,  its too much bandwith too, so it seems the mini pc is capable of over 4k 60hz. It seems the cable has more bandwith than HDMI 2.0, but not as much as advertised (48GBS) faulty cable? Thanks

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Baak 1 1 4 days ago

What happens if you use an HDMI 2.1 cable between NUC and TV?

Assuming you mean LG CX? This LG has 1 eARC HDMI input, is the CAC-1587 connected in this input?

Suharik 0 4 days ago

The PC has only fake HDMI 2.1 (tmds) which is basically 2.0, so no point.

the LG is CS indeed, not CX
CS is basically C1 with C2 chip

LG CS has HDMI 2.1 port (confirmed its working perfectly), and the cable is connected to it.

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Wiktor 2 0 4 days ago

This cable can easily handle 4k120Hz, so it’s not a problem with it, it’s a problem with compatibility.
LG’s family is notorious for causing problems at higher refresh rates, you could try this one:
https://www.reddit.com/r/Monitors/comments/hqha0d/custom_resolutions_on_club_3d_cac1085_with_lg/

Suharik 0 4 days ago

Will try it to night, and reply how it worked, thanks!

The PC has intel integrated GPU and driver, so hopefully it wont be a problem, as guide mentions nvidia.

Suharik 0 3 days ago

Unfortunately that didnt work, 2 things that could be a problem:
The guide mention that in extension block you need to add “DisplayID” type.
But i had only “DisplayID 2.0” and “DisplayID 1.3”, i dont have just “DisplayID”.
so i went with 2.0

Other problem is that the guide tells to set the custom resolution in nvidia control panel, but i have intel graphics, and their software doesnt have such feature, it just opens windows display settings to set there, and from there i get the same problem (so maybe its still using old resolution settings?)