Monitor resolution reduced when using multiple displays

Question

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

Answer 1

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.

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.