MST vs DisplayLink: How Windows Laptops Run Multiple Monitors
When a dock says "triple display", it's using one of two technologies to do it: MST or DisplayLink. They work very differently, and the right one depends on your laptop's USB-C port.
MST: your laptop's own graphics
MST stands for Multi-Stream Transport. It's part of the DisplayPort standard. Your laptop's graphics chip sends one DisplayPort signal down the USB-C cable, and the dock splits it into several monitors.
- No software. It works with the graphics driver Windows already has.
- Full graphics performance, with nothing extra running on your processor.
- Protected video plays normally, so streaming services work on every screen.
The catch is that your laptop's USB-C port must carry video. That means DisplayPort Alt Mode, USB4 or Thunderbolt. Also, all the monitors share one DisplayPort connection's bandwidth. That's why many MST docks list three screens at 4K 30Hz but only two at 60Hz.
Windows supports MST. Most MacBooks don't, which is why the same dock may only mirror screens on a Mac.
A driverless MST dock like the Kensington SD3210U3 runs three monitors this way.
DisplayLink: video over USB
DisplayLink uses a small chip in the dock and driver software on your laptop. The laptop compresses the picture and sends it as data over USB. The dock turns it back into video.
- Works on almost any USB port, even ones without video support.
- Runs more screens than some laptops allow natively.
But:
- You need the DisplayLink driver, and it needs updating now and then.
- It uses some processor power, which can matter on a slow laptop.
- Some protected video won't play. Streaming sites may show a black screen on DisplayLink monitors. The Anker Prime DL7400 listing warns about this.
Which should you choose?
- Your laptop has DisplayPort Alt Mode, USB4 or Thunderbolt: choose an MST or Thunderbolt dock. It's simpler and faster.
- Your laptop's USB-C port doesn't carry video, or you need more screens than it supports: choose DisplayLink.
- You use the same dock with a MacBook too: DisplayLink is often the only way to get more than one extended screen on a basic MacBook Air.
How to check your port
Look for a small DisplayPort symbol or a Thunderbolt lightning bolt next to the USB-C port. If there's none, check the laptop's spec sheet for "DisplayPort Alt Mode", "USB4" or "Thunderbolt". For five docks compared for Windows laptops, see our Windows laptop docking station comparison.