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U2721DE and U2724D daisy chain low resolution on second
Dell U2721DE
Hi,
I have a Windows 11 Thinkpad. U2721DE is used as primary monitor and docking (laptop is connected using USB-C cable, mouse and keyboard via USB-A cable). Got a new monitor U2724D and it is connected to primary monitor using DisplayPort. I keep my laptop lid closed while using monitors.
In this setup, I get full resolution (2560x1440) for primary monitor U2721DE, but the second monitor U2724D is at 1920x1080 (instead of full resolution same as U2721DE).
Suppose if I use only secondary monitor (windows + p, select second screen only), then I get full resolution (2560x1440) for secondary monitor (with primary monitor turned off/disabled).
Is there anything I should check to get both the monitors at full resolution?
Are U2721DE and U2724D compatible with each other?
Thanks
Chino de Oro
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August 27th, 2024 05:20
You should look into the bandwidth provided by the Thinkpad. The refresh rate can also affect the resolutions.
forgetmenotmyfrnd
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August 27th, 2024 05:51
@Chino de Oro thank you for your response. I see primary monitor has two refresh rates 60.01 Hz and 59.95 Hz. Secondary monitor has 5 refresh rates 30, 29.97, 25, 24, 23.98Hz.. Tried changing it, but does not help resolve the situation. I don't know how to check bandwidth provided by the Thinkpad. But I noticed, it has Thunderbolt port next to the power input.
Chino de Oro
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August 27th, 2024 05:53
What is the specific Thinkpad model and the graphics being used?
forgetmenotmyfrnd
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August 27th, 2024 06:06
It is T14s, Intel(R) Core(TM) i7-10610U CPU @ 1.80GHz 2.30 GHz, Intel(R) UHD Graphics.
Chino de Oro
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August 27th, 2024 06:30
USB-C supports up to 4096x2304 @60Hz. Therefore, it can not drive two Quad HD monitors.
https://psref.lenovo.com/syspool/Sys/PDF/ThinkPad/ThinkPad_T14_Gen_1_Intel/ThinkPad_T14_Gen_1_Intel_Spec.PDF
redxps630
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August 27th, 2024 13:03
Instead of daisy chain try to use a docking station for the thinkpad and connect both 1440p monitors to the docking station.
forgetmenotmyfrnd
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August 27th, 2024 16:55
@redxps630 - I tried using Thinkpad docking station, connected two individual DisplayPort cables to each monitor. It sometime works but most of the time does not work.
redxps630
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August 27th, 2024 18:32
what resolution do you have on each monitor when it does not work?
forgetmenotmyfrnd
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August 28th, 2024 00:55
@redxps630 my setup is U2721DE and U2724D, in daisy chain or with docking I get 2560x1440 on U2724DE and 1920x1080 on U2724D. One thing I noticed, when it works all fine, if the laptop goes to sleep due to inactivity, after waking up I see this problem.
Btw, there is another setup with Dell U2722DE and U2722D, I noticed my Thinkpad in daisy chain works just fine and both monitors are connected has full resolution (2560x1440) at 59.95 Hz refresh rate. There is no issue even when laptop goes to sleep and wakes up.
Thanks
Chino de Oro
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August 28th, 2024 01:39
As long as you use monitors with 60 Hz, you can get dual setup with resolution of 2560x1440.
Your U2724D sent EDID signal for 120 Hz, therefore the resolution had to scale back to lower settings.