X1 Tablet 2nd Gen with USB-C and USB 3.0 Pro Docks

A Lenovo X1 Tablet is a marvel of engineering in terms of packing a lot into a small space. But it’s so small, there are very few external connectors:  one USB-C which also functions as a power supply port, one USB 3.0, and one mini DisplayPort. To use this machine as a desktop replacement, you need a dock. Turns out, not all docks are created equal.

To make a long story short, I bought a USB-C dock (40A9), had lots of problems with it, returned it, and got a USB 3.0 Pro dock (40A7) instead.

The two monitors that I want to run through the dock are a Dell U2410 (1920×1200 @ 60Hz) and an old SyncMaster 213T (1600×1200 @ 60Hz).

Here’s my experience in tabular form:

  USB-C Dock 40A9 USB 3.0 Pro Dock 40A7
Supports my two external monitors No, max two @ 1920×1080. Connecting both my monitors caused flickering on and off. Yes, max two @ 1920×1200
Computer can boot with dock attached Often hangs on red “Lenovo” screen Yes
Allows monitor connected via DisplayPort to sleep No, Dell monitor kept waking up every few seconds; had to manually turn off monitor when not in use. Yes
Allows PXE boot from wired network adapter Yes Yes
Allows AMT vPro control from wired network adapter No No
Combines power supply and data connection in one cable Yes; leaves USB 3.0 jack on computer open. No; requires discrete power supply for computer plus the use of the tablet’s only USB 3.0 jack.
List Price (U.S.) $199.99 $179.99
Price on Amazon (U.S.) $113.41 New $75.88 Used – Very Good

Note that there is also a USB 3.0 Ultra dock (40A8). Compared to the USB 3.0 Pro, the Ultra has an extra USB port and substitutes HDMI for the Pro’s DVI video port. My older monitor has DVI but not HDMI, so the Pro dock was actually a better match (though it does require that I use an extra external USB hub, which is working fine).

The USB-C is a nice idea especially with being able to supply power and data through one cable. But in practice, it falls short. The USB 3.0 Pro dock, based on the widely-used DisplayLink hardware and drivers, looks like it will be the more capable and reliable choice.

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