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USB to HDMI

3 min read

mentioned in 2024-11-28

USB-C Alternate Mode

USB-C video cables or adapters are cheap (30) and easy to find. They can convert USB C to:

  • HDMI
  • DP (Display Port)
  • DVI
  • Component Video
  • VGA
  • etc.

The most common are to HDMI and DP.

Since the video standards are built into the hardware and specifications, they are just plug-and-play, and they take no configuration, no special drivers, and no extra CPU resources.
The USB is used as a DP without tranforming the data in any way, it uses the native USB pins.

If your computer is older and has no USB-C ports, or if all of your video outputs and USB-C ports are taken up on your computer, or if you don’t have an output built into your computer that can support 4k at 60Hz, then you can use a special proprietary “DisplayLink” hardware/software solution to give you more monitor output at up to 5k at 60 Hz using standard USB-A 3.0 ports.

DisplayLink has been around since 2007, and is widely supported by a lot of adapters today. Expect it to be 2.510x more expensive (150) than a comparable USB-C adapter, however. It is now owned by https://www.synaptics.com.

It uses special drivers you have to install on your computer plus a special “DL” DisplayLink hardware chip in the adapter, to force any USB 2.0 or 3.0 port to become an external video card.

Therefore, it also uses extra CPU resources on your computer, unlike the USB-C to video adapters above.

DisplayLink over USB 2.0 is limited to a max resolution of 2048 x 1152, according to here: “Maximum resolution supported: 2048 x 1152”. Check the specs of the particular DisplayLink device you buy. It may be lower resolution than this.

DisplayLink over USB 3.0 on the latest DL-6xxx can support up to 1 video output at 5k 60Hz (5120 x 2880) or 2 simultaneous video outputs at 4k 60Hz (up to 4096 x 2160). That’s incredible. I’m sure it’s going to use quite a few extra CPU resources to make this happen, however. If you choose HDMI, be sure your version of HDMI supported by the monitor itself can support 4k at 60 Hz. My monitor only supports 4k at 60Hz using the DP cable, not using HDMI.

Read about the different IC generations here, and ensure you know which IC your device you are going to buy has: https://en.wikipedia.org/wiki/DisplayLink#IC_Generations

Common inexpensive ($40) 2k 60Hz adapters like this use the DL-3500 chip and support resolutions up to 2048 x 1152 at 60Hz or 2560 x 1440 (2k, 1440p) at 60Hz.

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