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How to Run Two Monitors from One DisplayPort Cable (MST)

Updated · Standard formula, shown below

This guide explains how to use Multi-Stream Transport (MST) to run two monitors from a single DisplayPort output on your computer. You’ll learn how to set up an MST hub or a docking station with DisplayPort daisy-chaining, what cables and hardware you need, and how to troubleshoot common issues. By the end, you’ll have a dual-monitor setup working from one port on your PC or laptop.

What You’ll Need

  • A computer with a DisplayPort 1.2 or newer output (check your GPU or laptop specs).
  • An MST hub (also called a DisplayPort splitter) or a docking station that supports MST.
  • Two monitors that support DisplayPort (or have DisplayPort inputs). If your monitors only have HDMI, you’ll need active DisplayPort-to-HDMI adapters.
  • DisplayPort cables (at least two, one from PC to hub, one from hub to each monitor).
  • Optional: A USB-C to DisplayPort cable if your computer only has USB-C with DisplayPort Alt Mode.

Step-by-Step

  1. Check your computer’s DisplayPort version. MST requires DisplayPort 1.2 or higher. On Windows, right-click the desktop and select “Display settings” → “Advanced display settings” to see your GPU model. On a Mac, check System Information under “Graphics/Displays.” If you’re unsure, look up your GPU or laptop model online.
  2. Connect the MST hub or docking station to your computer. Plug the DisplayPort cable into your computer’s DisplayPort output and the other end into the hub’s input port. If you’re using a docking station, connect it via USB-C or Thunderbolt as directed by the manufacturer.
  3. Connect the first monitor. Take a DisplayPort cable and plug one end into the hub’s first output port and the other end into your monitor’s DisplayPort input.
  4. Connect the second monitor. Repeat the same with the hub’s second output port and your second monitor. If your monitor only has HDMI, use an active DisplayPort-to-HDMI adapter (passive adapters won’t work for MST).
  5. Power on the monitors and the hub. Most MST hubs are bus-powered, but some require an external power adapter. If they don’t light up, plug in the power supply.
  6. Turn on your computer. Wait for it to boot and detect the monitors. On Windows, right-click the desktop and select “Display settings.” You should see two monitors listed. If not, click “Detect.” On macOS, go to System Settings → Displays; it should show both.
  7. Configure the display layout. In the display settings, arrange the monitors to match your physical setup (drag the rectangles). Choose “Extend these displays” from the multiple displays dropdown to use them as separate screens.
  8. Set the resolution and orientation. Click on each monitor rectangle and set the recommended resolution and orientation (landscape or portrait).

Common Mistakes

  • Using passive DisplayPort-to-HDMI adapters. These only work for a single monitor. For MST, you need active adapters that convert the signal properly.
  • Plugging the hub into a DisplayPort output that doesn’t support MST. Some GPUs disable MST on certain ports. Check your GPU’s manual or try a different port.
  • Using a cable that’s too long. DisplayPort cables over 3 meters (10 feet) may degrade the signal, causing flickering or no display. Use shorter, high-quality cables.
  • Forgetting to update graphics drivers. Old drivers can cause MST to fail. Update your GPU drivers from the manufacturer’s website.
  • Assuming all docking stations support MST. Some cheaper docks only mirror the display. Check the dock’s specs for “MST” or “multiple displays.”

Tips

  • Use the same resolution and refresh rate on both monitors to avoid compatibility issues. If one is 4K and the other 1080p, the hub may downscale the higher one.
  • If you have a laptop, make sure it’s plugged in. Some laptops disable MST on battery to save power.
  • Label your cables to avoid confusion when connecting.
  • Keep the hub in a well-ventilated area to prevent overheating, which can cause intermittent disconnects.
  • If you’re using a docking station, check for firmware updates from the manufacturer. Many MST issues are fixed with firmware.

Troubleshooting

No display on one or both monitors: First, check that all cables are securely connected. Try swapping the cables between monitors to see if the issue follows the cable or the monitor. If it does, replace the faulty cable. If not, try a different output port on the hub or computer. Also, ensure the monitors are set to the correct input source (DisplayPort, HDMI, etc.).

Monitors are detected but show a black screen: This often means the resolution is set too high for the MST bandwidth. Lower the resolution to 1080p and see if it works. Also, try reducing the refresh rate to 60Hz.

Only one monitor works: This could be because your GPU doesn’t support MST on that port, or the hub is faulty. Test the hub with a different computer if possible. Also, check if your GPU’s control panel has an MST setting that needs to be enabled (e.g., in NVIDIA Control Panel, under “Set up multiple displays”).

Flickering or intermittent signal: This is usually a cable issue. Replace with a certified DisplayPort cable (VESA certified). Also, try moving the hub away from other electronic devices that might cause interference.

MacOS not detecting the second monitor: Some Macs require a specific MST hub that supports the Mac’s implementation. Check the hub’s compatibility with macOS. Also, try resetting the NVRAM (restart and hold Command+Option+P+R).

Windows shows both monitors but they mirror: Go to display settings and select “Extend these displays” instead of “Duplicate these displays.”

Frequently Asked Questions

Can I use an MST hub with a laptop that only has USB-C?

Yes, if your USB-C port supports DisplayPort Alt Mode. You’ll need a USB-C to DisplayPort adapter or a docking station that uses USB-C. Check your laptop’s specs to confirm.

Does MST work with HDMI monitors?

Yes, but you need active DisplayPort-to-HDMI adapters. Passive adapters won’t work because they don’t carry the MST signal.

Can I daisy-chain monitors instead of using a hub?

Yes, if your monitors have DisplayPort out ports. Connect the PC to the first monitor, then from its DisplayPort out to the second monitor. This uses MST internally.

Will MST reduce the refresh rate?

It can, especially at high resolutions. For example, two 4K monitors at 60Hz might exceed the bandwidth of DisplayPort 1.2. You may need to lower the resolution or refresh rate.

Do I need a special graphics card for MST?

Most modern GPUs from AMD, NVIDIA, and Intel support MST. Integrated graphics on some older CPUs may not. Check your GPU’s specifications for “MST support.”

Can I use three monitors with an MST hub?

Yes, if the hub has three outputs and your GPU supports the bandwidth. However, the total resolution and refresh rate will be limited by the DisplayPort version.

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