When I want to connect 2 4K monitors, but the resolution is low

[Dom11111]

When I want to connect 2x 4K monitors, the resolution of the first one is 4K but 30HZ and the second one is QHD with 60HZ. Why this docking station cannot hold dual 4K monitors with 60 HZ? In manual there is written that it should be possible.

[BeemerBiker]

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@Dom11111 wrote:

When I want to connect 2x 4K monitors, the resolution of the first one is 4K but 30HZ and the second one is QHD with 60HZ. Why this docking station cannot hold dual 4K monitors with 60 HZ? In manual there is written that it should be possible.

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You did not mention the Host PC.

It must be capable of driving the docking station.  There are two types of G5 Dock and specifications are different

Possibly the Host PC cannot meet the specifications of the G5 you are using. This could possibly be fixed by changing the resolution, refresh rate and color depth to meet the bandwidth of the Host PC.

HDMI DisplayPort, USB-C Docking, splitters Possible resolutions click here



Using this bandwidth calculator you can find the bits per second mimimum required throuput for the video signal.

USB types and speed explained here

Some HP docking stations

USB-C Doc G5

USB-C G5 Essential Dock

Please provide the Product ID or exact model name of the Host PC for better assistance. Preferably the full product ID including the characters after the # symbol. 

[Dom11111]

It is USB-C Doc-G5, but the host PC is not HP, it is Dell Latitude 5440, may it be a compatibility issue?

[BeemerBiker]

This spec for your Dell shows it has thunderbolt 4 which is good.  I assume you connected to the Dock using the Thunderbolt 4 port.  The problem may  be  that the GPU cannot drive three different displays at different resolutions, refresh, and color depth.   Does your laptop have graphics built into the CPU or does it have a separate GPU such as Nvidia.  You can ask over here but I suspect they will tell you to replace the HP dock with one of theirs.

Start by trying to get all three displays to work using minimum settings

Use FHD 1920x1080 for laptop, and both monitors. Set the refresh to 30.

See if that works then try raising the external monitors up FHD => QHD =>  UHD

The higher resolutions require move video memory.

From ChatGpt:  how much video memory to run 3 monitors at UHD

To run 3 monitors at UHD (4K) resolution (3840x2160), the amount of video memory (VRAM) required is significantly higher than for Full HD monitors. Here’s a detailed breakdown:

Basic Calculation

• Each UHD monitor requires approximately 3840×2160×43840 \times 2160 \times 43840×2160×4 bytes per pixel (assuming 32-bit color depth).
• This equals about 32 MB per frame per monitor.

Memory for Frame Buffers

• For 3 monitors, this would be approximately 32×3=9632 \times 3 = 9632×3=96 MB just for the frame buffers.

Additional Overheads

• Textures and Off-Screen Buffers: Additional VRAM is used for textures, off-screen buffers, and other graphical data.
• 2D Applications and Desktop Work: Even simple tasks require more VRAM at higher resolutions.
• 3D Applications and Gaming: These applications require significantly more VRAM, especially at 4K resolution.

Recommended VRAM

1. General Use (Browsing, Office Work, Watching Videos):
   • At least 4 GB VRAM to ensure smooth performance.
2. Gaming and 3D Applications:
   • At least 8 GB VRAM is recommended for modern games at 4K resolution.
   • High-end gaming or future-proofing: 10 GB VRAM or more.
3. Professional Work (Video Editing, CAD, 3D Modeling):
   • Depending on the software, 8 GB VRAM might be the minimum.
   • For high-end applications or very demanding tasks: 12 GB VRAM or more.

Summary:

• General Use: At least 4 GB VRAM
• Gaming/3D Applications: 8 GB VRAM or more
• Professional Work: 12 GB VRAM or more

Make sure your graphics card supports multiple 4K monitors and has the necessary outputs (HDMI 2.0, DisplayPort 1.2 or higher). Additionally, consider the overall power and cooling requirements of your setup when choosing a high-VRAM graphics card.

[Dom11111]

My laptop has INTEL UHD  with a dedicated memory 128mb, and shared memory 8034mb. When I try to connect 1 monitor directly to the laptop by HDMI and 1 monitor to my docking station, it works fine. I just cannot have 2 UHD monitors connected through docking station, I don't know why. They say that 2x4K connected through my dock should work, but not. https://h20195.www2.hp.com/v2/getpdf.aspx/4aa7-5464enw.pdf

[BeemerBiker]

It looks like that Dell should work but I am only familiar with their Area51 system.

There is a firmware update for the Dock

https://support.hp.com/us-en/drivers/usb-c-docking/model/27767206?sku=5TW10ET

you may need driver updates for the Dell. 

There is an Intel update app that might work on the dell

Did you try setting resolution down low for all 3 displays: laptop, monitor 1, monitor 2 .

Do all work at 720

then try 1k 

then 2k

You might look at the windows task manager resources and see if the Dell is maxing out all its memory.

GPU-Z can show if the graphics is always running at %100 .,

 using this tool (GPU-Z) and selecting 'sensors'