I have a problem when I use DP1.4 to connect 1080T

I have a problem when I use DP1.4 to connect 1080TI with spectrum, I can’t turn on 4k@120, 8bit, RGB/YCbCr444,ihave to use YCbCr422.
In theory, bandwidth is enough, do you have any ideas?
The first report of the same content was sent on 29 August 2021.

But I just got an useless automatic email reply,so I decided to come here and ask.

2021/10/11,I received an email reply,it‘s say

“ NVIDIA GTX 10-series cards do not offer all DisplayPort 1.4 features, and display stream compression (DSC) is not supported. That means that the ports on the graphics card do not have enough bandwidth to support the maximum resolution and refresh rate of Spectrum without applying some form of chroma subsampling, and do not have the compression technology required to squeeze this information into the available bandwidth. There was a customer with a similar question some time ago, you may be able to find a fitting reply by going back through previous support tickets. ”

Can someone tell me what “NVIDIA GTX 10-series cards do not offer all DisplayPort 1.4 features” is?

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I mean in theory it should work but likelihood is Windows colour management is the p.o.s that’s giving you a hard time, assuming windows 10 is the OS you’re using.

I believe DP 1.4 has an effective rate 25-26gb/s which means bandwidth isn’t enough to get RGB/4:4:4 at 120hz as far as windows 10 is concerned…if you dropped it to 98hz that might work as it should free up the bandwidth to make space for it.

Otherwise dropping to 422 you should be able to use even 144hz and likely turn on HDR as well (if windows lets you turn on HDR because WIndows colour management is stupid lol)

In fact, I’ve tried 100hz,98hz,90hz,75hz,and still couldn’t run until 4K60hz(I can run 444/RGB with 4K60).This is the part that confuses me the most. :confused:

As a cost of guaranteed bandwidth,I use 8bit instead of 10bit,but the problem is the same.
(My native language is not English, the above content is translated by software)

I’m having the same problem.

alienware r7
windows 11
8700k
1080ti
dp1.4 cable
nvidia drivers
472.12
510.06

Apart from the problem of not being able to run 120hz/RGB/4:4:4, I am also having problems with variable refresh rates, so I am currently using it with G-sync turned off.
With G-sync on, the screen will randomly black out. And random stuttering.

I can only hope that these issues will be resolved in a future monitor firmware update.

Oh wow that is very odd. Hopefully someone can chime in on this.

Maybe @Lore_Wonder can help with getting a ticket submitted with the support team? Since you haven’t received a response.

Which Spectrum firmware are you using? Have you updated to the latest 104 version to see if it makes a difference?

The 104 firmware can be found on the evedevices.com support page. Click on DOWNLOADS (just above the big black CONTACT US heading) and expand the Firmware section under Spectrum ES07D03.

If you need more info on how to update the firmware, there’s a thread for that.

These problems are caused by the monitor’s firmware 104.

As for the variable refresh rate problem, we have found that after turning on the variable refresh rate in the OSD menu, unplugging the DC plug of the monitor and waiting at least 5 seconds before plugging it back in improves the problem in some applications. (This may be a coincidence, but…)
However, there are still some applications that have problems, so I use nvcp to set each application to a fixed refresh rate.

As for the problem of not being able to run 4k hdr rgb 444, I will test it again when my newly purchased dp1.4 cable arrives.

Thank you for your reply.
I discussed it with you on the forum not long ago,when I used 102 firmware.
https://eve.community/t/hdmi-2-1-or-dp-1-4/28894/38?u=sora714
Now i use 104 firmware,but the problem remains.

Thank you for your reply.
The problem has been with all firmwares.

I am having this exact same issue with my Spectrum monitor as well.

Anything above 1440p @ 60hz and 4K @ 60hz on my 1080ti forces the YCbCr422 color space and it looks to be unchangeable.