Review on 💻 Lenovo ThinkPad Thunderbolt 3 Dock Gen 2 135W (40AN0135US): Dual 4K Display, HDMI, DP, USB-C, USB 3.1, Black by Gabe Smith

UPDATE 2: Coming back to 3 stars, I found that the main issue is that if you touch the TB3 cable even a little bit (between dock and laptop), the sync fails. Given the number of dropout complaints here and on Reddit, I suspect it's an issue with the TB3 connector on the back of the dock, which isn't isolated to me. I had the same issue with a 2018 MacBook Pro with a discrete GPU (enough power to run those monitors). UPDATE: Originally rated 4 stars, but after prolonged use I'm seeing a lot of disconnects and loss of one or both external monitors. So I'm downgrading to 1 star. I realized that this dock or the X1 Yoga is not powerful enough to drive two 4K monitors at 60Hz. If I could return it I would. I bought one of these to use with the X1 Yoga (Gen 3) hoping to eliminate the clutter and connect 2 external 4K monitors, both 60Hz. TL version; DR: You will need a DisplayPort cable (HDMI 2.0 may also work) for one monitor and a Thunderbold 3 -> DisplayPort cable for the other. Monitor 1 connects to one of the DP ports on the back of the dock, and Monitor 2 connects to the Thunderbolt 3 (USB-C) port on the front of the dock. Both monitors must have DisplayPort 1.2 enabled and not in daisy chain mode. According to the Windows 10 display settings, my monitors are: 1: Yoga internal LCD 2560 x 1440 @ 59Hz 2: Dell P2715Q at 3840 x 2160 @ 59Hz 3: LG 27UD69P at 2160 x 3840 @ 59Hz (portrait) On the Dell, I had to go into the OSD menu and disable "MST" under the "Display" menu item. (This is where you specify whether it should work as primary or secondary when chained.) On the LG, I had to go into the OSD and enable "DisplayPort 1.2" under the "General" menu item. (Disabling it limited it to 30Hz for some reason.) Your mileage may vary, but that's how I got it working for me after deciphering some documents from the Lenovo support site and Reddit forums.