So when I got my new iMac Pro (as my MacPro 4,1 finally bit the bullet) I decided to get an OWC Thunberbolt 3 Dock with 14 ports and 85 watts of power to connect more peripherals to my Mac.
Overall I love Other World Computings products and their service. They are a great company, but the problem with this device for me is the mini displayport.
I have the iMac Pro and an LG 4k 27 inch monitor. I was trying to hook up the LG via the mini displayport in the dock. First I tried an Amazon basics mini displayport cable to displayport cable and it just didn’t work at all.
Then I tried an Amazon basics mini displayport to HDMI connector. This seemed to work, and both monitors worked, but whenever the computer slept the displays and woke back up the second monitor acted as if it was just found, and all the windows that were on it would be moved to the iMac Monitor. Super frustrating especially when using, Premiere Pro, After Effects or DaVinci Resolve across both monitors. The display also did the same thing when I connected or disconnected anything to the dock, including my iPhone or iPad using the front high powered ports, or the SD cards!
I thought maybe it was the connector, so I spent quite a bit more money and went to apple and got the Belkin mini display port to HDMI that they listed since I didn’t see a direct one from Apple. When I got it, it had the exact same problems.
I contacted support, and they got back to me very quickly, and after some back and forth, basically it came down turning sleep off, but I didn’t want to do that, nor turn off let hard drives sleep, as I don’t want to ruin my RAIDs by having them run all the time.
So after being frustrated for a while I went for a USB 3.1 to HDMI adapter, and this I connected to the back of my awesome OWC ThunderBay 4’s Thunderbolt port, and the monitor works great now! Everything (well almost everything, as Messages seems to jump back to the iMac monitor quite a bit) stays on the second monitor when the computer sleeps and I can leave everything going to sleep!
And I can connected and disconnect things with the dock without any issues. The dock works great when I am not using it for it’s mini displayport connector. I am not sure if my dock has an issue with it’s mini displayport, or if this is just an issue with this dock and an iMac Pro, but it is something to know in advance.