Dual 4K @ 60Hz monitors via USB-C with DisplayPort 1.4

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 in 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.

  • HP Dock G5
    • 100W Power Delivery
    • DP 1.4 HBR3 with DSC for 2x 4K60 alongside USB 3.x @ 5Gb/s when DSC is active on the host PC. See PDF spec sheet,
    • Compatible with TB3 and USB-C systems, however several Surface Laptop 3 and Pro 7 customers have not had good results with this dock on launch firmware (see comments below). Updated firmware may help.
  • Goodway DUD2070
    • 85W Power Delivery
    • DP 1.4 HBR3 with DSC for 2x 4K60
    • Unclear if USB 3.x runs at 5Gb/s alongside display – need more info from vendor
  • Goodway DBC14A0
    • 60W Power Delivery
    • DP 1.4 HBR3 with DSC for 2x 4K60
    • Unclear if USB 3.x runs at 5Gb/s alongside display – need more info from vendor
  • Club3D CSV-1563
    • DP 1.4 Alt Mode -> HDMI+DP + 3xUSB + PD 100W + Ethernet
    • launch canceled
  • Wavlink WL-UTD21 / Winstars WS-UTD21 TB3
    • 60W Power Delivery
    • DP 1.4 for 2x 4K60
    • Uses Titan Ridge JHL7440 chipset offering TB3 AND USB-C 3.x host compatibility
    • As of 12/11/2019, Daisy@Wavlink says that 2x 4K60 will not work on Surface Pro 7 and neither will 10GB/s USB 3.x.
  • Plugable TBT3-UDZ
    • Launching in Q2 2020
    • 100W PD
    • DP 1.4 with DSC for 2x 4K60 in USB-C mode
  • HyperDrive Gen2 hubs (6, 12, 18-port)
    • Launching in Q2 2020 via Kickstarter
    • 100W PD
    • DP 1.4 with DSC for 2x 4K60 in USB-C mode

Option 2 – USB-C -> DP 1.4 MST hub

More USB-C -> DP 1.4 hubs are expected to start shipping in 2020. 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 – Monitor 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, but there is a catch. There is a 3-6 frame lag/latency making a poor gaming experience. Office and most creative workloads like CAD/photo/video-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.

23 thoughts on “Dual 4K @ 60Hz monitors via USB-C with DisplayPort 1.4

    • Yes I believe so but I have not tested this personally. You will need to use two DisplayPort cables and setup the monitor in the Intel or AMD control panel (15″ laptop) accordingly to use both cables and align the two halves of the screen.

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  1. Please, I need your help, I got a surface pro 7 i7 and the HP dock G5 but it’s not working with 2 4k monitors (actually not even with one)
    On the website field of your reply form I put the link of hp forum where I fully describe what’s happening.
    I feel a bit desperate right now…

    Like

  2. Hi Dan,

    Thanks for all those useful information here.

    I can confirm, that “Cable Matters USB-C 2x DisplayPort + 1x HDMI2.0 triple 4K MST hub” does not work as intended:

    Pro: Display options together with Surface Pro 7 and even a OneMix Yoga S2 (w/o DP 1.4 support) are great – Dell U4919DW works with both.

    Contra: As soon as I connect a PD power supply the display connection stops working (on both devices menioned above). Therefor I assume it is not connected to the Surface, but an issue of the Cable Matters hub.

    I hope this is getting better in the next month – for now I need to send it back.

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    • Thanks for posting this and sorry it did not work out. Sounds like buggy firmware in the hub.

      Before you send it back, would you mind trying a couple things? Does it matter if you plug in the PD power BEFORE plugging in the monitors and USB-C connector?

      Do either of the laptops charge through hub with or without monitors attached?

      Can you observe any changes in Device Manager during all this? It would be interesting to see if the USB-C device disappears from the system entirely or if it is just the monitors that disappear.

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  3. Hi Dan,

    sorry for the late reply & thanks for your answer.

    I tried those things out:
    – no change in behavior whether PD, USB-C or DP resp. HDMI are connected first
    – if no PD is connected everything works fine
    – as soon as PD is connected the device manager continuously refreshed and the screens are disconnected
    – no charging via PD in any constellation
    – device manager shows “PD USB-C Device”, but only if no PD power supply is connected

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  4. I have a Surface Laptop 3, the LG 34WK95U-W display (5120×2160 @ 60 Hz) and the “Cable Matters USB C Multiport Adapter (USB C Hub with DisplayPort 8K), 2X USB 2.0, Fast Ethernet, and 60W PD in Black – USB-C and Thunderbolt 3 Port Compatible”.

    It works, but if power goes through it, there are random split second interruptions (happening once every few minutes) in video and potentially power which make my monitor produce a disconcerting popping sound. If PD doesn’t go through the dock (only video and USB) there are no issues whatsoever. I am using it without power attached to it to avoid damaging my monitor which is almost as expensive as the laptop.

    This is oddly similar to Leo’s issues above with the HP dock. I was actually thinking of purchasing the HP dock but found this thread. I wonder if the problem is actually in the firmware of the Surface.

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  5. Hi Dan,

    I also purchased a Cable Matters 4K Triple Display USB C Hub to be used together with my Surface Pro 7 and Lenovo X1 Yoga (Gen4) and I also have the same USB-C power problem as Michael on the Surface Pro 7. Cable Matters has confirmed to me that this hub has limitations when used with SP. PD can’t be used at the same time when monitors are connected. The say that it’s because the way Microsoft has implemented it’s USB-C internals but I think that’s quit odd?! When I power up the SP with only the hub and power connected, the SP is charging but no external signal. So charging ánd driving two screens simultaneously is a no go…

    The Yoga dóes work with this hub but it needs to be connected to power and monitors béfore booting the system. Then everything works as expected. Connecting he hub when the system has already been started results in the same behaviour as with the SP7…..

    Like

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