Can not do 10 bit & +144 Hz at the same time

[Honigfluss]

Hi. I can not set my refresh rate above 120Hz with 10-bit color depth. It automatically switches to 8-bit. Even though my monitor claims 170Hz, it's only usable at a maximum of 120Hz with 10-bit. Is this a cable or monitor issue?
My monitor model: VX2780J-2K
Cable: Ugreen 80391 DisplayPort 1.4 cable.
GPU: 4070

[dilpickle]

It would help to know what the monitor is.

[GuiltySpark_]

The monitor you have might be useful to know. And your GPU.

[Honigfluss]

2 minutes ago, dilpickle said:

It would help to know what the monitor is.

 

2 minutes ago, GuiltySpark_ said:

The monitor you have might be useful to know. And your GPU.

Sorry, I forgot to mention my specs. I have edited the post.
My monitor model: VX2780J-2K
Cable: Ugreen 80391 DisplayPort 1.4 cable.
GPU: 4070

[Honigfluss]

15 minutes ago, dilpickle said:

It would help to know what the monitor is.

 

14 minutes ago, GuiltySpark_ said:

The monitor you have might be useful to know. And your GPU.

Here is the specifications of my monitor: ViewSonic VX2780J-2K 27” 2K 170Hz IPS Gaming Monitor - ViewSonic Europe

[OhYou_]

it is a bandwidth issue.
you can try forcing it if you want, go make a custom resolution in nvidia control panel that has 10 bit and 144hz, and be sure to change timings to cvt reduced which will lower the bandwidth a bit.

[Honigfluss]

19 minutes ago, OhYou_ said:

it is a bandwidth issue.
you can try forcing it if you want, go make a custom resolution in nvidia control panel that has 10 bit and 144hz, and be sure to change timings to cvt reduced which will lower the bandwidth a bit.

Like that? I don't really know about custom resolutions.

[Honigfluss]

I got duplicate resolution warning.

[Honigfluss]

I have no idea how to test it... I changed a setting to CVT, hit test button, lost signal for 30 seconds and it automatically came back to the native resolution. Also there is no setting to select 10-bit color depth.

[OhYou_]

11 minutes ago, Honigfluss said:

Like that? I don't really know about custom resolutions.
 

well you should set colour depth (bpp) to... why is it 32. I guess set that to 40, not sure why its 4x bit depth, rgbw maybe.
set that to 40 for 10 bit

set timing >standard > CVT reduced Blank or any one of them that says reduced.
set refreshrate to 144

if you get a black screen for 15+ seconds then the monitor wont do it

[Honigfluss]

20 minutes ago, OhYou_ said:

well you should set colour depth (bpp) to... why is it 32. I guess set that to 40, not sure why its 4x bit depth, rgbw maybe.
set that to 40 for 10 bit

set timing >standard > CVT reduced Blank or any one of them that says reduced.
set refreshrate to 144

if you get a black screen for 15+ seconds then the monitor wont do it

The only option for bpp is 32. Can't i use 10 bit at higher hz values like a normal human being? Where is this bandwith issue coming from? I don't get it.

[OhYou_]

39 minutes ago, Honigfluss said:

Where is this bandwith issue coming from? I don't get it.

you can use this handy calculator to see the raw data of the issue, https://tomverbeure.github.io/video_timings_calculator
actually it seems your display is already using reduced timings, you can maybe squeeze more out of it but I dont think it will matter
basically your monitor at 144hz 8 bit uses 15.44Gb/s
if you increase that to 10 bit, it uses 19.3Gb/s
you can tweak timings down to 16.5Gb/s

[GuiltySpark_]

The display is likely DP 1.2 limiting you to 8-bit+FRC at 170Hz. 

 

There is nothing remarkable about that display anyway that setting it to 10-bit is going to change, regardless. 

 

If it was a higher end HDR capable display it would be a problem, but that display would likely also have DP 1.4/HDMI 2.1. 

[Honigfluss]

1 hour ago, OhYou_ said:

you can use this handy calculator to see the raw data of the issue, https://tomverbeure.github.io/video_timings_calculator
actually it seems your display is already using reduced timings, you can maybe squeeze more out of it but I dont think it will matter
basically your monitor at 144hz 8 bit uses 15.44Gb/s
if you increase that to 10 bit, it uses 19.3Gb/s
you can tweak timings down to 16.5Gb/s

 

36 minutes ago, GuiltySpark_ said:

The display is likely DP 1.2 limiting you to 8-bit+FRC at 170Hz. 

 

There is nothing remarkable about that display anyway that setting it to 10-bit is going to change, regardless. 

 

If it was a higher end HDR capable display it would be a problem, but that display would likely also have DP 1.4/HDMI 2.1. 

This display already has displayport 1.4 port guys. Why are you all talking like it is displayport 1.2?

[GuiltySpark_]

27 minutes ago, Honigfluss said:

This display already has displayport 1.4 port guys. Why are you all talking like it is displayport 1.2?

Can you prove / confirm that? If it did, 1440p @ 170Hz 10-bit would be no problem. 

 

DP 1.2 gives you just enough bandwidth to run at 170Hz 8-bit. Just a theory since there are no reliable review sources or tests. 

 

Just because your monitor suggests a bunch of features, doesn't mean it can do them all at the same time. Classic marketing obfuscation. 

[Honigfluss]

Just now, GuiltySpark_ said:

Can you prove / confirm that? If it did, 1440p @ 170Hz 10-bit would be no problem. 

 

DP 1.2 gives you just enough bandwidth to run at 170Hz 8-bit. Just a theory since there are no reliable review sources or tests. 

 

Just because your monitor suggests a bunch of features, doesn't mean it can do them all at the same time. Classic marketing obfuscation. 

Literally every single source says it has a DP 1.4 port, including its official website. ViewSonic VX2780J-2K 27” 2K 170Hz IPS Gaming Monitor - ViewSonic Europe

So we are 100% sure this monitor is capable of displaying 10 bit at 170 hz at 2K, right? In this case, looks like I got scammed by amazon, because I ordered this cable: Ugreen 80391 8K 60 Hz Display Port To Display Port 1.4 Örgülü Kablo 1.5 Metre, Siyah : Amazon.com.tr: Bilgisayar

The one that came to me is not exactly same tho, there is no unlock button on it and 2 sharp protrusions on the end.

[Honigfluss]

So as far as I understand, there is no thing like " This monitor has a DP 1.4 port but it is not capable of displaying 10 bit 170 hz 2k at the same time ", right?

[xg32]

4 hours ago, Honigfluss said:

So as far as I understand, there is no thing like " This monitor has a DP 1.4 port but it is not capable of displaying 10 bit 170 hz 2k at the same time ", right?

something's limiting it to 1.2, it's not the 4070, not the cable, so it's the port on the monitor, setting it to 8bit and the frc or the gpu will make it 10bit anyway.

[Honigfluss]

9 hours ago, xg32 said:

something's limiting it to 1.2, it's not the 4070, not the cable, so it's the port on the monitor, setting it to 8bit and the frc or the gpu will make it 10bit anyway.

I bought a new cable which will arrive tomorrow. If it does not work with that cable too, I'm try windows 10 format + windows 11 to see if it will fix my problem. I will refund it if i can't use dp 1.4.

[Glenwing]

Some monitors have menu options that control the DisplayPort feature level, try checking for this.

[Honigfluss]

30 minutes ago, Glenwing said:

Some monitors have menu options that control the DisplayPort feature level, try checking for this.

Mine does not have such ability. I asked about this to viewsonic, its been 3 days and im still waiting for a reply.

[Thaldor]

Because your monitor only supports 8 bit + FRC, so it's either "10 bit" at 120Hz OR 8 bit at 170Hz.

Directly from the ViewSonic

 

There isn't any loop around that because the monitor itself is acting as HDR monitor and taking that 120Hz 10 bit signal and then changing it to 8 bit + FRC at that 120Hz, which is probably close to normal 8 bit at 170Hz because FRC is basicly just flickering two 8 bit colors to mimic 10 bit color.

[Glenwing]

7 hours ago, Thaldor said:

Because your monitor only supports 8 bit + FRC, so it's either "10 bit" at 120Hz OR 8 bit at 170Hz.

Directly from the ViewSonic

 

There isn't any loop around that because the monitor itself is acting as HDR monitor and taking that 120Hz 10 bit signal and then changing it to 8 bit + FRC at that 120Hz, which is probably close to normal 8 bit at 170Hz because FRC is basicly just flickering two 8 bit colors to mimic 10 bit color.

That makes no sense, the use of FRC is not related to refresh rate, nor does the system know whether the monitor uses FRC or not; it just sees a 10 bpc display.

[Thaldor]

On 3/3/2024 at 7:30 PM, Glenwing said:

That makes no sense, the use of FRC is not related to refresh rate, nor does the system know whether the monitor uses FRC or not; it just sees a 10 bpc display.

The couple monitors I have seen with FRC have been like that. I must say I haven't dug enough there since I decided to go directly native 10 bit supports so didn't need to look deeper. But I would guess it's about that the panel itself can do max. 170Hz so the FRC must also fit into that, which means the "refresh rate" of 10 bit content must be slower than 170Hz to make time to fit that flickering between two colors within the refresh rate of the panel.

Much easier to explain what I mean with 3D TV's and glasses. The 3D content requires that per one frame of the content the TV must show 1 frame per eye to create the 3D effect, this means if the TV has a panel that has 120Hz refresh rate (120 frames per second) it can only do 60 "fps" 3D content, it is still doing 120Hz/fps but the content must run half of that because the frames are divided between eyes.

 

Same with FRC, the FRC must flicker two 8 bit colors to recreate a 10 bit color, this will eat the rate at which the monitor can show content because it needs to show more frames per frame of the content to recreate the 10 bit colors. The system exactly doesn't know the monitor uses FRC so the monitor must slow down the rate at which the system sends content so the monitor has time to show the content with FRC, so it just tells the system the refresh rate is lower.

[Glenwing]

3 hours ago, Thaldor said:

The couple monitors I have seen with FRC have been like that. I must say I haven't dug enough there since I decided to go directly native 10 bit supports so didn't need to look deeper. But I would guess it's about that the panel itself can do max. 170Hz so the FRC must also fit into that, which means the "refresh rate" of 10 bit content must be slower than 170Hz to make time to fit that flickering between two colors within the refresh rate of the panel.

Much easier to explain what I mean with 3D TV's and glasses. The 3D content requires that per one frame of the content the TV must show 1 frame per eye to create the 3D effect, this means if the TV has a panel that has 120Hz refresh rate (120 frames per second) it can only do 60 "fps" 3D content, it is still doing 120Hz/fps but the content must run half of that because the frames are divided between eyes.

 

Same with FRC, the FRC must flicker two 8 bit colors to recreate a 10 bit color, this will eat the rate at which the monitor can show content because it needs to show more frames per frame of the content to recreate the 10 bit colors. The system exactly doesn't know the monitor uses FRC so the monitor must slow down the rate at which the system sends content so the monitor has time to show the content with FRC, so it just tells the system the refresh rate is lower.

It is because a DisplayPort HBR2 transmission is limited such that 170 Hz and 10 bpc are not possible at the same time at 1440p.

 

It is a straightforward bandwidth limitation and is not related to how 10 bpc color depth is implemented (FRC or not). Since the monitor advertises "DP 1.4" hopefully this means it supports HBR3 speed, so this would not apply. That is what the discussion above was about.

 

Panels are addressed in a matrix format where only 1 row of pixels is actually connected to the controller at any given time. The controller scans through every row in order over the course of 1 refresh cycle. It is not possible to go back and change the color of a pixel twice during one refresh cycle as this would simply be the same has having a twice as high refresh rate, and this capability would not be wasted on simply implementing FRC.

 

FRC operates by changing the color on alternating refresh cycles, not within a single cycle.

 

My suspicion is that the monitor only supports HBR2 speed, and when ViewSonic says it has "DP 1.4" they just mean it supports HDR or something else. I should note the user manual states only "DP 1.2".