I recently bought the Dell S2721QS (4K @60 Hz) and would like to add a second monitor with a high refresh rate. I have a Surface Book 2 which only has a USB-C port and two USB 3.1 ports. What's the best way to go about docking dual monitors? Is it possible to get a USB-C monitor and daisy-chain that to the S2721QS? What's the highest resolution and refresh rate I could support on the second monitor? Any help is appreciated.
Cheers
Great analogy mate, thanks. So those USB-C hub monitors (such as the Dell P2722HE) are still limited by the USB-C bandwidth?
Yes it has to be, it's a limitation of the standard. That's why USB-C hubs can usually only do 4K 30Hz, as this only takes up two lanes and leaves some for USB 3.1.
You could run two monitors if you got the Surface Dock 2 but you would be capped at 4K 30Hz which would run through the proprietary surface connector port on your surface book and has USB-C inputs by default (you could buy HDMI to USB-C to USB-C to C cables to run into the monitor). This would save your USB-C port on the notebook for another use.
More details on it are on the MS website: https://support.microsoft.com/en-us/surface/identify-your-su…
Other than that I don't think based on having the one USB-C port that isn't thunderbolt that you could drive two monitors if one is 4K already.
Cheers for the info, that's dissapointing. I wonder if I could do two monitors with the Surface Dock 2 with one 4K 60 Hz and the second one 1080p 60 Hz? Or if the 4K one would still be limited to 30 Hz
It might be possible with a third party dock but because you're using a Surface Book 2 I'm not sure if the dock will also be able to power the device via USB-C. There are docks that have chipsets built in that will do the work to allow dual 4K at 60Hz with a software download. From what I remember a Surface Book 2 needs about 102W of power to function which puts it just out of reach of most third party docks that only deliver somewhere between 65W and 100W.
I wouldn't know what to recommend because I'm not sure if the Book 2 will allow charging via USB-C and the MS proprietary port at the same time.
Basically, the best analogy to understand this is that USB-C is a highway with four lanes. Each lane can carry either USB signal, or DP (alt-mode) signal.
Each lane, in DP alt-mode can carry the equivalent of 1080p 60 Hz. So therefore, you might have a dock which can carry 2 x 1080p monitors and some USB ports, let's say. If you are running 4K 60 Hz, then you are already consuming all four lanes of the USB-C highway, as a 4K monitor is equivalent to four 1080p monitors. In other words, you cannot connect any further monitors to that particular port.
Note that this is in reference to USB-C, not Thunderbolt 3/4 which also uses the same connector, but is a different standard. Think of it in a similar way, but with 4x the bandwidth, so you can easily carry 2 x 4K 60Hz and still have bandwidth left over for USB signals.