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DP Bandwidth issue when monitor source input has changed, need urgent help

sth9634
Beginner
816 Views
Hello arc community users.

Before we start, my setting is,
4k@144hz monitor with PS5(HDMI) and PC with A750(DP) connected.

Simply, I am suffering for bandwidth issue of arc A750 when I change source for monitor.

When I change source to PS5(hdmi) and come back to PC(DP), PC framerate is capped at 4k@60hz.
Not always 60fps, but following bandwidth for hdmi 2.0(4k@60, 1440p@120, etc. I can select one of those).
After rebooting, I can finally select 4k@144hz as normal.

I’ve tried a few solutions,
1) install driver after DDU -> same
2) install older driver -> same
3) change VGA to friend of mine(3070ti) -> solved

Therefore, it seems the problem is, ARC A750.
Of course, reBAR is on, tried VRR on and off, hibernate on and off.

Is there any solution for it? Should I change VGA?
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MUC
Valued Contributor III
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Please state the make and model of the monitor.

 

Is the cable connection straight?

PS5 ------ HDMI cable ------ monitor

PC ------ DP cable ------ monitor

 

Please create Reports for Intel Graphics Drivers and attach the output files here. One for the OK situation and one for the NOT OK situation.

 

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sth9634
Beginner
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The monitor is, S32DG700 from Samsung.

 

Yes, cables are directly connected to the monitor.

 

I made reports, but weirdly, it says 4k@60fps is max mode? 

Anyway, I made two. One for operating 4k@120fps, the other for when operating 4k@ capped 60fps.

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MUC
Valued Contributor III
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Samsung Odyssey G7 G70D
3840 x 2160 @ 144 Hz 10-bit HDR (CVT-RB) and
VESA AdaptiveSync (48 - 144 Hz)
if "Input Signal Plus" and "Game Mode" are set to ON

 

  • 2 x HDMI 2.1 FRL
  • 1 x DisplayPort 1.4a

 

The Extended Display Identification Data (EDID) that the monitor sends is the same in both cases according to the diagnostic reports you attached. However, the data is not conclusive because 144 Hz VESA CVT-RB does not occur and should be included in a DisplayID extension block, which is not shown in the driver report. Please do the following in the situation where everything is working as it should:

 

Run edid-test.exe:

https://www.monitortests.com/edid-test.zip

 

This will create a file named "edid-test.txt" in the same folder. Please attach this TXT file here.

 

Don't worry. This data is just encoded data of the information sent from the monitor to your PC. No personal data or other system information is read through it.

 

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sth9634
Beginner
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Here you are.

But that is kinda weird, as I am using it in 4k@120hz right now.

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sth9634
Beginner
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Problem has solved with suggestion I've got from other community.

 

He said, 'It was happening as preferred resolution was not checked on maximum possible'.

I do not understand what that meaning is exactly, but program named CRU, which he used, actually showed that monitor is giving resolution range as 48~144hz in 4k, and 144hz was not checked as preferred resolution.

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MUC
Valued Contributor III
629 Views

EDID is read from the monitor by the PC's graphics driver over the cable and tells the driver what the monitor can do. This EDID is stored in the Windows registry. With CRU it is possible to perform what is known as an EDID override. This does not delete the original data, but creates a replacement that is marked as an override and can then be used by the driver. The Windows operating system offers this possibility. edid-test.txt shows the correct EDID of your monitor:

 

MUC_0-1737751419117.png

 

The Intel diagnostic report does not show the EDID that the driver is actually processing.

 

But since 120 Hz worked for you before, the driver actually processes Block 2 as well, because that's where that information is contained (and also the 144 Hz information). If you didn't already know, I would have suggested performing an EDID override. This is relatively easy and can also be undone if necessary. The standard procedure would be:

 

  • Download the EDID file attached (EDID_SAM_G70D_DP.txt)
  • Download Custom Resolution Utility (CRU)
  • Run CRU.exe
  • Make sure the active EDID is SAME06F connected to your PC. If necessary, select from the drop down menu

    MUC_1-1737752433403.png

     

  • Close CRU with OK and restart the computer.

     

 

Note:
All changes made with CRU can be undone if necessary by running "reset-all.exe" from the CRU download package and restarting the system. You can find more information about this tool on the linked page.

 

As you already know:

 

MUC_2-1737753642735.png

 

(1) The EDID of a display device that has been changed is marked with a star icon
(2) Edit DisplayID Extension Block
(3) The preferred detailed resolutions are marked with a star icon
(4) You can set it as you like and change the order

 

If you know what you are doing, the advantage of EDID override is that the settings will always be preserved once the same display device is detected when the Windows graphics driver loads.

 

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