Triple Monitor Flickering

[tawdry ravine]

When I turn on my 3rd monitor, 2 screens start to flicker. It doesn't matter which 3rd monitor it is that's on. I can only use 2 monitors at a time. Not a cable issue, it happened to my gf's PC earlier this week too.

[lusty adder]

In order to understand your problem/issue further, we would like you to provide additional specs of your PC/Laptop. Please provide the following specs:

• Laptop Model (If you are using a laptop)
• CPU Model
• Motherboard Model
• RAM Model & Speed (Please tell us if you have enabled XMP or using custom timings)
• GPU Model
• SSD/HDD Model & Capacity (Specify where is Windows installed to)
• PSU Model & Capacity (Not applicable for laptop)
• Windows Version (Please also state the Windows version as well, such as 23H2 or 24H2, etc.)
• Monitor model, resolution, refresh rate and cable used (HDMI or DisplayPort)
• Apps & games you are trying to run (Please also specify where you get your games from like Steam/Battle.net/Xbox Game pass)

In addition to the following specs, we would like you to answer the following questions:

• Have you reinstalled the Nvidia Drivers by removing them with DDU and reinstalling them by downloading the drivers manually and installing them?
• Have you made any changes to your PC/Laptop in the past few days (such as software/hardware install)?
• Have you encountered any error codes/bluescreens/graphical glitches when encountering the problem? Describe steps to reproduce the problem. Please send a photo/screenshot/video of the problem here as well.

[midnight quail]

for both PCs as well as their attached monitors.

[tawdry ravine]

pc, amd 7800x3d, idk the motherboard or the ram, 32 gb of ram though, 4090, ssd with a bunch of space, not sure on the windows version

basically my gf has a totally different set up from mine too and it happened to her earlier this week

we replaced the cables thinking it was that, but it still persisted

then i had her restart her computer and it fixed itself

i restarted my computer twice, this just randomly started happening for me today

and its still doing it

so not really sure what the reason is

updated all drivers too

[midnight quail]

Well, almost everything is known except the monitor models themselves now

[cunning crest]

1. Dell U2719D - 1440p 60hz

2. ASUS ROG Swift OLED PG32UCDP - 4k 240hz

3. Optix G27C5 - 1080p 165hz

So the 2nd monitor is the problematic once since it's a high refresh rate monitor with only HDMI 2.1 and DP 1.4

You basically just engaged DSC

[lusty adder]

If you are experiencing display issues, graphical artifacts, dithering or black screens especially on high resolution and high refresh rate monitors like the Samsung G9, it may have been caused by DSC (Display Stream Compression) being enabled. Display Stream Compression was developed to reduce the amount of data that is required to be transmitted between the video source, like what a graphics card is, to a monitor or TV. The goal is to compress the video stream without degrading the quality and therefore allowing higher resolutions and refresh rates. The need for DSC arises as the connections between the source and the monitor or TV are limited by the capability of the ports and cables alike. If the GPU detects that a display supports DSC, DSC mode will be enabled automatically if the display exceeds the bandwidth of the ports (HDMI or Displayport). Please check the model of your monitors, the GPU and the ports on your GPU & monitor with the respective manufacturers (LG, Samsung, Nvidia, AMD, Intel) to determine the maximum supported resolution with & without DSC. For more details on bandwidth & resolutions can be found here: Guide to Display Cables / Adapters (v2) - Displays - Linus Tech Tips

For Nvidia GPUs:
Using a monitor/display with DSC support over DisplayPort 1.4+:

• Display Stream Compression over DisplayPort 1.4+ is supported on Turing class (GeForce RTX 20-series/GeForce GTX 16-series) and higher GPUs.

Using a monitor/display with DSC support over HDMI 2.1:
-Display Stream Compression over HDMI 2.1 is supported on Ampere class (GeForce RTX 30-series) GPUs.

• While you may use a an older GPU (eg. GeForce GTX 10-series) with a display that supports Display Stream Compression over DisplayPort 1.4+/HDMI 2.1, you may not be able to select the highest resolution or refresh rate supported by the display.
• When a display is connected to the GPU and is set to DSC mode, the GPU may use two internal heads to drive the display when the pixel rate needed to drive the display mode exceeds the GPU’s single head limit. This may affect your display topology when using multiple monitors. For example if two displays with support for DSC are connected to a single GeForce GPU, all 4 internal heads will be utilized and you will not be able to use a third monitor with the GPU at the same time.
• NVIDIA DSR, NVIDIA DLDSR and NVIDIA Image Scaling are not supported when DSC mode is enabled for 40-Series GPU and below.
• If the GPU detects that a display supports DSC, DSC mode will be enabled automatically. Some displays may allow you to disable DSC by changing the communication link from the displays internal settings (eg. changing the DisplayPort mode from Displayport 1.4 to DisplayPort 1.2)

To determine if your PC monitor, notebook display or TV supports Display Stream Compression, please refer to your display manufacturer.

A monitor that uses DisplayPort 1.4 or HDMI 2.1 with DSC may cause reduced amounts of available video connections.

A GeForce GPU internally provides up to four display heads. For most monitors, each monitor connection uses one display head.

Very high end displays that use DisplayPort 1.4 or HDMI 2.1 with DSC utilize enough bandwidth that they use two display heads for one monitor. This will reduce the maximum available displays used with a single GPU.

On DisplayPort 1.4a with HBR3, if a monitor's capabilities exceed the rough equivalent of 4K120 (3840x2160 at 120Hz), including other resolution equivalents (e.g. 1080p400 (1920x1080 at 400Hz) or 1440p250 (2560x1440 at 250Hz)), the display might utilize DSC. (Some capability is lost due to timing requirements.)

To use the maximum amount of displays with such monitors with a single GPU, use the monitor's OSD to disable DSC, or use an alternative, lower-end connector if available.

Alternatively, if your CPU has an iGPU, you can enable it (if it's not enabled by default), and plug any extra monitors to the motherboard's display output(s) instead.

As a third option, if your computer does not have an iGPU or motherboard display outputs, and has extra physical PCIe x16 slots (does not need to be electrically x16) with at least two slots' worth of clearance, you can add another video card to immediately add extra video outputs. If using an NVIDIA card, make sure that the driver you're using supports both video cards; mixing driver versions is not allowed, so very old cards may be unusable.