[Updated 2020/05/06 with more product info]

Most laptops shipped through Q2 2019 with USB-C ports (not Thunderbolt 3) support external monitor connections via “DP Alt mode”. These laptops support DisplayPort 1.2 (DP 1.2) with a single 4K60 monitor or 2x 4K30 monitors via multi-stream transport (MST) technology. A drawback of driving hi-resolution monitors on these ports was USB devices being limited to USB 2.0 speeds.

Some newer laptops like the Surface Pro 7, Surface Pro X, and Surface Laptop 3, have expanded capabilities on their USB-C ports supporting DisplayPort 1.4 (DP 1.4) with Display Stream Compression (DSC) to drive 2x 4K60 monitors alongside USB 3.x @ 5Gb/s+. Below are a few options for driving dual 4K60 monitors on these newer laptops.

Option 1 – USB-C multi-function Dock/hub with DP 1.4

Multi-function docks supporting DP1.4 are quite new and several models shipped with buggy initial firmware during Q3 2019. We will update this list with known issues and firmware updates when available.

Option 2 – USB-C -> DP 1.4 MST hub

The drawback to these hubs is that they do not offer USB A or Ethernet connectivity. Pairing these with a wireless keyboard/mouse is a good option for a full desktop rig if you don’t need any wired USB devices. Most of these devices appear to be based on the latest Synaptics VMM53xx/VMM52xx DP1.4 MST chipsets.

Option 3 – USB-C -> DP 1.4 adapter -> DP 1.4 MST hub

While not recommended due to potential compatibility issues from connecting multiple cables/adapters in series, combining an adapter and a hub will work for many customers. Again, this approach does not include Ethernet or USB A ports.

Adapters:

DP 1.4 hubs:

Option 4 – Monitors supporting DP 1.4 MST daisy chaining

This approach takes advantage of monitors that integrate DP 1.4 transceiver chipsets and support MST daisy chaining. Only the first monitor in the chain needs to support DP 1.4 in order to run two 4K60 monitors. The second monitor can be either DP 1.2 or DP 1.4. The first monitor in the chain must have:

two DisplayPort receptacles, one DP 1.4 upstream, and one DP 1.x downstream OR

one USB-C upstream receptacle and one DP 1.x downstream receptacle

The monitor documentation needs to explicitly list DP 1.3 or DP 1.4 MST support. Very few monitors support this as of Q4 2019:

Option 5 – DisplayLink technology

Another option is to use DisplayLink Display-over-USB technology. This approach allows adding 2-4 4K60 monitors without needing DP 1.4 so it will work on any USB-C laptop. But there is a catch. There is a 3-6 frame lag/latency making for a poor gaming experience. Office and many creative workloads like CAD/photo-editing work OK.

DP 1.4 aka DP8K Cables

Do note that any connections between monitors and devices passing DP 1.4 bandwidth may need to be made with “DP8K” ready cables, otherwise resolution and refresh rates can be limited. Several vendors offer DP 1.4 aka DP8K ready cables. Don’t rush out to buy DP8K cables if you already have DisplayPort cables though – for short runs, older cables will probably work OK. More info on adapters and cables.

References and related Chipset spec sheets

Special Thanks to Mark for passing along the link to the PDF for the HP Dock G5.