2 of 3 extended screens blink or flash frequently, cutting video stream & audio stream

Good Evening,

I purchased a Plugable UD-ULTC4K for my brand new Macbook Pro 13" in November of 2023. The primary use for this is running the streaming for my YouTube Live Streaming. However, two of the three monitors always blink or flash, cutting the video and the audio, resuming after a second.

I have good quality computer monitors and one 32" TV for extended displays. All three are connected via quality HMDI cables that are 15 - 20’ long (to reach my recording tripod from my podium).

If I do not have any programs open, they do not blink, or blink much. If I open a browser, YouTube, or ECamm (my streaming software), it blinks incessantly. Originally I thought it may be refresh rate settings, but I checked that I’ve 60 hz on the diplays, and their resolution are set to 1920 x 1080.

I’ve exhausted eliminating variables and cannot solve this problem, so I’m reaching out to you guys for help. We have hundreds of Plugable Docking Stations at my business, and I love your products. But this one that I’m using for personal use is giving me fits!

Thanks in advance for your help.


Hello RC,

Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

One immediate issue I noticed is the length of cables that you are using. For the video outputs we generally recommend only 6 to 10 feet in length as the video signal may be unstable for longer length cables. Are you able to test temporarily using shorter cables to see if the issues remain or if that does help?

You may also be running into issues with video outputs being unstable because generally the DisplayLink USB graphics technology this dock uses for two of the three video outputs is not intended for the kind of software you’re using. This is because DisplayLink USB graphics isn’t using hardware acceleration or able to support advanced graphics software, it’s a virtual graphics solution driven by the DisplayLink Manager app installed on your Mac.

So for example, your streaming software may be having compatibility problems with the DisplayLink based outputs due to these limitations. The DisplayLink outputs also do not support HDCP (copyright protection) which can cause additional problems for some streaming apps and video playback from protected sources (screens will black out if protected content is played).

For your use case scenario we would typically instead recommend a Thunderbolt 4 solution (not using DisplayLink USB graphics) as the video is driven using the higher end capabilities of the graphics chipset in your Mac and would offer hardware acceleration, HDCP, etc that DisplayLink is not able to offer. The primary drawback of this however is that Macs are limited to only two displays through Thunderbolt at this time. So there would be a tradeoff for better performance, but less screens.

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

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