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I am using 2 external monitors connected to my laptop through a USB-C hub. One monitor has a maximum resolution of 2560x1440 and the other has 1920x1080. When I connect to both the monitors using HDMI to USB-C hub to USB-C, both the monitors give a maximum resolution of 1920x1080. How can I fix this so that my 2K monitor gives 2K resolutions?

When I connect only the 2K monitor, it gives a resolution of 2560x1440. My laptop has a resolution of 1920x1080. My laptop is Lenovo Thinkpad L390 Yoga running on Intel(R) Core(TM) i7-8565U with Windows 11 Home (22000.348). This is the USB-C hub I am using - https://www.amazon.com/dp/B08N546LKM?psc=1&ref=ppx_yo2_dt_b_product_details

rnp
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    Please edit the question and include information about which hardware you have. – Gantendo Dec 01 '21 at 03:53
  • Your laptop has a maximum resolution it's graphics subsystem can push. This will be published in the specs of the GPU. What is your GPUs max resolution? – music2myear Dec 01 '21 at 04:23
  • @music2myear my GPU has a maximum resolution of 4096x2304. How is the total resolution calculated when using multiple monitors? – rnp Dec 01 '21 at 04:41
  • This is a complex scenario as it depends on the exact model of your laptop and the exact model of USB-C hub. It is typical that USB-C hubs and laptops have limitations on the number of external monitors and what resolution and refresh rates are possible. It's not uncommon that multiple monitors would force lower resolution and/or refresh rates. TL;DR, this might be all your hardware can support, but we need full model details to help you further. – spaceman-spiff Dec 01 '21 at 09:51
  • @spaceman-spiff I added the hardware details I am using. Please let me know if I need to provide something else. – rnp Dec 01 '21 at 13:35
  • Added an answer, but make sure your Lenovo has the latest BIOS updates and make sure your Intel UHD graphics driver is also up-to-date. If the dock has drivers, update those. – spaceman-spiff Dec 01 '21 at 20:25

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The Intel UHD Graphics 620 should, in theory, work, but there could be shortcomings in that dock since it only offers HDMI and not Display Port connectors - details here https://www.intel.com/content/www/us/en/support/articles/000057629/graphics/graphics-for-8th-generation-intel-processors.html

Your laptop supports the following:

  • 2 x USB-C 3.1 Gen 1 (support data transfer, Power Delivery and DisplayPort™ 1.2)
  • HDMI 1.4b

It is possible you have some bandwidth reductions happening via the USB-C dock that are restricting the resolution at various refresh rates since there is no Display Port channel passing through the dock. Also, the HDMI 1.4b on the Lenovo may be restricted to low refresh rates at higher resolution.

While your monitors are connected, check your available display rates and modes by searching settings for "View advanced display info" and then select your display in question and click 'Display adapter for Display xx'. Then click the List All Modes button to see possible resolutions. That will tell you what the display is possible of showing with the current adapter. If your desired mode is not available, it is likely a limitation of the dock.

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It's not clear from your original post if this issue is present if you try connecting one monitor to the Lenovo's HDMI port and the other monitor to the HDMI port on the dock. If you haven't, try that as you might be able to achieve it when splitting the display connections between the laptop and the dock rather than both displays via the HDMI ports on the dock.

spaceman-spiff
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    Thank you for the detailed response. It did give me a lot of new understanding. Splitting the connections - one directly from lenovo and one from the dock worked! Thanks for the suggestion. – rnp Dec 01 '21 at 22:24
  • A different dock that has Display Ports instead of, or in addition to, HDMI, *might* yield a different result. But if splitting the connections doesn't hinder you, then you ought to be fine. At any rate, glad it helped. Upvotes on the answer always appreciated. – spaceman-spiff Dec 02 '21 at 01:25
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    I wanted to upvote both your comment and the answer, but there is a reputation threshold of 15 to do that which I do not have. I personally opine that one should be able to upvote on his questions irrespective of the reputation – rnp Dec 02 '21 at 03:32