TBT3-UDV Thunderbolt 3 docking station to two external Dell P2715Q monitors @ 60Hz not working

I recently got a TBT3-UDV Thunderbolt 3 docking station to use with my two Dell P2715Q 4k monitors. I specifically chose this docking station as I have seen other docking stations are not compatible with this particular monitor. I have connected one of the monitors to the display port in the docking station and the other using the Thunderbolt 3 to display port cable. With this configuration, I am only able to run at 30Hz using the MST set to primary and secondary. But, I am not at all satisfied with this as the primary reason I chose this docking station is to connect my two 4k monitors @ 60Hz. Can you please help?

Hello Sridutt,

Thanks for contacting us! To run two monitors at 4K @ 60Hz you will need to not use an MST configuration. Instead you must run one monitor from the DP port on the dock and the second must be connect via the second Thunderbolt 3 port using a USB-C to DP or HDMI adapter cable.

Thank you,
Joshua Henry
Plugable Technologies

Hi Josh,

I am exactly doing as you have suggested. One of the monitors is running from the DP port on the dock and the second one is connected via the second Thunderbolt 3 port using a USB-C to DP.

With this configuration, if the MST is turned off only one of the monitors (the first one to connect) works.

The only way that I could figure out to run both of monitor is to use MST in this same configuration. But that drops the refresh rate on both the monitors to 30Hz (which is not acceptable to me).

I have already read everything, including watching the video on your manual page (https://plugable.com/products/tbt3-udv/) before posting here to see if I could do something else. But, I couldn’t find a solution that works.

I can share any further info if you need and will be happy to try anything else that you might want me to do.


What make and model laptop are you connecting the dock to?

Sorry, I forgot to mention it earlier. But, I am using a MacBook Pro (13-inch, 2017, Four Thunderbolt 3 Ports) running Mac OS High Sierra Version 10.13.5.

Thanks for the information. This confirms my suspicion. MST is not supported on Mac systems for anything except for specialty 4K and 5K monitors that use MST internally to operate. https://support.apple.com/en-us/ht206587

Thanks for your reply Josh! Did you point me to the article to suggest that two 4k monitors are not supported by my Mac at 60Hz? I didn’t clearly get that. But, I want to add that I am able to run my monitors at 60Hz by connecting one of the monitors through the docking station and the other through one of the Thunderbolt 3 ports on the Mac. I don’t have to use MST in this case. I was hoping something similar could work with the docking station. I don’t want to plug to two Thunderbolt ports as I think it defeats the purpose of having the docking station in the first place.

Hi Sridutt,

Thanks for the update. I mainly linked to the article in case there were questions on what MST is/isn’t supported. But I do think we have a solution for you.

You can use a USB-C to HDMI or DP adapter/cable to connect your second monitor at 4K 60Hz to the second Thunderbolt 3 port on the back of the dock.

So something like this:


Hi Josh,

Thanks for the suggesting the solution. But, I have been doing exactly the thing you have suggested with the Thunderbolt 3 to DP port. Only that I am not using a plugable adapter cable. Is it required that I use plugable specific one?

Also, PFA the pics of my setup. Hope this can help better with suggesting a solution.

Sridutt !](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1740059/IMG_0341_inline.jpg?1531257459)](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1740059/IMG_0341.jpg?1531257459)

Thanks for the update! A cable like that *should* work, however we have seen where some cables aren’t fully compatible before. Unfortunately we’ve not tried that specific model before so it’s hard to say with confidence that it will work.

I want to dig a little deeper into this issue. Can you send us an email directly at support@plugable.com with your Amazon Order ID # or other proof of purchase, the serial # off the bottom of the dock, and the best shipping address? Please just reference ticket # 228948 in the subject line.


Thanks Josh! I will get back to you shortly with the details you have asked for.

I was able to get my problem resolved offline with the prompt help and support from Josh.

The problem in my case was that the Thunderbolt 3 cable between the dock and computer was not able to provide the full bandwidth of 40Gbps and so my two Dell P2715Q monitors only worked when I used them with the MST setting. Josh was quick to point this out and kind enough to send me a free replacement that arrived in only two days.

I am very pleased and satisfied! I will highly recommend this docking station to anyone looking for now.

PS: To the folks at Plugable it will be great if you can add a line in your description on Amazon and your product page that this docking station works with Dell P2715Q as I have seen many people suggesting that your previous docking stations didn’t work with this particular monitor. Kudos to you all! :slight_smile: