How to Set Up Two Computer Monitors

Опубликовал Admin
1-07-2018, 20:00
Community Tested This wikiHow teaches you how to use two monitors with the same desktop computer. You can do this on both Windows and Mac computers, though you'll need a computer with a graphics card that supports multiple displays if you're using Windows.

On Windows

  1. Make sure that your computer supports multiple monitors. On the back of your computer's CPU box, you should see at least two horizontal ports near the bottom of the box; these are connections for your computer's graphics card, which is what you'll need to use to set up two monitors.
    • You cannot use the default monitor connection, which is typically a vertical slot in the middle of the CPU box, to set up multiple monitors.
    • Vertical ports are connected to the motherboard, while horizontal ports are connected to the graphics card.
    • If you don't see the proper ports on the CPU box, you'll need to install a graphics card before setting up a second monitor.
  2. Determine the type of connection you'll need. Look at the graphics card's ports and your computer monitors' respective inputs to see which of the following you'll need:
    • DVI - Wide piece of plastic with numerous small square holes in it.
    • VGA - Trapezoid-shaped piece of colored plastic with several pinholes in it.
    • HDMI - Thin, flat, hexagonal port.
    • DisplayPort - Similar to HDMI, but has a flat edge one one side instead of being symmetrical. Necessary for 4K displays.
    • Thunderbolt - Found on the backs of most iMac monitors; has a lightning bolt icon beneath it. You can connect an adapter for any of the above video connections to a Thunderbolt port (e.g., VGA to Thunderbolt).
  3. Buy any cables that you don't have. If your computer's graphics card's inputs require DisplayPort cables, for example, purchase them for both monitors.
    • If your monitors don't support the graphics card's cable type (e.g., DisplayPort), you'll need an adapter or a cable that has two connections (e.g., a DisplayPort connection at one end and an HDMI connection on the other end).
  4. Turn off your computer. It's easiest to connect the second display without running into issues when the computer is powered off.
  5. Plug the first monitor into one graphics card slot. To do this, you'll most likely need to unplug the monitor from the vertical motherboard port into which it's currently plugged and then plug it into the horizontal graphics card port.
    • If your first monitor's motherboard connection is different than the graphics card connection, you'll need to use a different cable with the monitor.
  6. Attach the second monitor. Plug the second monitor's cable into another graphics card slot, then plug the other end of the cable into the back of the second monitor.
  7. Plug the second monitor into a power source. Using the power cable that came with the monitor, attach the monitor to a power source (e.g., a power strip or a wall outlet).
  8. Turn back on your computer and the monitors. Press the "On" switch for your computer and each of the monitors.
  9. Open Start . Click the Windows logo in the bottom-left corner of the first monitor's screen.
  10. Open Settings . Click the gear-shaped icon in the lower-left side of the Start window.
  11. Click System. It's a computer monitor-shaped icon in the Settings window.
  12. Click the Display tab. You'll find this option in the upper-left side of the window.
  13. Click the "Multiple displays" drop-down box. It's near the bottom of the window. A drop-down menu will appear.
    • You may have to scroll down to find this option.
  14. Select a display option. In the drop-down menu, click one of the following:
    • Duplicate these displays - Replicates the first monitor's display on the second monitor.
    • Extend these displays - Stretches the first monitor's display across both monitors.
    • Show only on 1 - Shows content only on the first monitor.
    • Show only on 2 - Shows content only on the second monitor.
  15. Click Apply. It's below the selected display option. This will prompt your second monitor to display part or all of your first monitor's content, depending on your selected display option.
  16. Click Keep changes when prompted. Doing so saves your settings. You can now use your second computer monitor alongside your primary one.

On Mac

  1. Determine the type of connection you'll need. In order to attach another monitor to your iMac, you'll need to use a cable for the back of the iMac's display. Look for one of the following ports on the back of the iMac:
    • Thunderbolt - Small, square port with a lightning bolt above it. Thunderbolt-to-Thunderbolt is the easiest way to connect two Mac displays to each other, but you can buy an adapter for any computer port (e.g., Thunderbolt-to-VGA) if necessary.
    • HDMI - Wide, thin, hexagonal port. HDMI is the industry standard for audio and video connections, so any monitor that you buy should support it.
  2. Buy any cables that you don't have. If your second monitor requires an HDMI cable, for example, buy an HDMI cable.
    • If you bought a monitor that only supports an older video standard (e.g., VGA), you'll need to buy a Thunderbolt-to-port (or HDMI-to-port) adapter (e.g., Thunderbolt-to-VGA).
  3. Plug the monitor's cable into the back of the iMac. If you're using an adapter, you'll first plug the adapter into the iMac's back.
  4. Attach the monitor to a power source. Plug the power cord that came with the monitor into a power source (e.g., a wall socket or a power strip).
  5. Turn on the second monitor. Press the monitor's "On" button to do so. You should see your Mac's desktop appear.
  6. Open the Apple menu . Click the Apple logo in the top-left corner of the primary screen. A drop-down menu will appear.
  7. Click System Preferences…. It's at the bottom of the drop-down menu.
  8. Click Displays. This computer monitor-shaped icon is in the System Preferences window.
  9. Click the Arrangement tab. It's at the top of the Displays window.
  10. Determine the type of display you want. If you want to use the second monitor to stretch your Mac's display across both screens, you'll uncheck the "Mirror Displays" box; if you want to display the same content on both screens, you'll check the "Mirror Displays" box.
  11. Move the menu bar if needed. If you want to place the menu bar (the grey bar at the top of the screen) on the second display, click and drag the white bar that's on the image of the monitor over to the second monitor.
  12. Exit System Preferences. Close both the Displays window and the System Preferences window. You should now be able to use your second display in conjunction with your primary Mac display.


  • Most laptops support HDMI (Windows, Mac), USB-C (Windows, Mac), and/or Thunderbolt (Mac only) connections. To connect a second monitor to a laptop, you need only attach the second monitor's cable to the laptop's video output port, after which point you can set up the monitor like you would for a desktop computer.


  • If you attach a second monitor that has significantly higher resolution than your first monitor, you may notice graphical clipping or other issues when switching between monitors. It's best to buy a monitor that matches your primary monitor's resolution if possible.
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