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ThinkPad UltraDock not supporting dual monitors

2018-06-19, 12:40 PM

I have a lenovo carbon running windows 10. The lenovo is connected via the power/video out cable to a Lenovo ThinkPad USB-C UltraDock With 90W 2 Prong AC Adapter (40A90090US). the dock is connected to two dell u2518d monitors (from bestbuy) via separate DP to DP cables. I also tried the DP to mini DP (with mini DP going into the monitors). No matter how I configure it, one of the monitors works perfectly with 125% sizing and 2560x1440, both of which are "recommended". The other monitor, however, does not show the same recommended sizing or resolution. instead it shows 100% recommended, and does not have 2560x1440 as an option - i can only select 2048x1080. I have tried several different configuration. i called tech support and they were useless. can you help please?


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Re: ThinkPad UltraDock not supporting dual monitors

2018-06-19, 13:00 PM

Probably not enough bandwidth to pump 8Mp (2*2560*1440) 60 times per second. Try reducing screen refresh rate to 30Hz in settings, this might help. 


User guide for the dock is not promising much:


Maximum resolutions and refresh rates

To achieve better display experience, it is recommended that you connect one or two external monitors to the dock at a time.

• DP output only: 3840 x 2160 pixels (30 Hz)

• VGA output only: 1920 x 1200 pixels (60 Hz)

• DP and VGA simultaneous output: 1920 x 1080 pixels (60 Hz) 

• DP and DP simultaneous output: 1920 x 1080 pixels (60 Hz)

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