I recently bought a laptop (Dell XPS-13), which comes equipped with only a Mini-DisplayPort for video, which is not compatible with most displays I have to use (university projectors). USB-ports are obviously available. I need to convert one or the other output to HDMI.

I assume there are differences in the nature of the conversion required in each case and need to know whether there is any characteristic or limitation in either conversion process that would make one inherently inferior to the other. Is there a video quality difference between a Mini-DisplayPort-to-HDMI adapter and a USB-to-HDMI adapter?

  • It's been pointed out that the question is misleading and I seem to have gotten a downvote for it. It's my first question and I genuinely tried to make it the best I could. Is the problem the mismatch between the question title and body? My rationale for that was to write a general (and thus useful) question, but still explain my specific situation. A general answer to the question is still an answer to my specific case. Or is it just that the question is uniteresting, unfit for this site or simply badly put? I'm not trying to complain, just to understand where I went wrong.
    – Heihej
    Dec 4, 2015 at 18:45
  • The question contained a lot of extraneous information related to your purchase decision-making, which is off-topic (could also have been interpreted as asking for opinions, also off-topic). The underlying issue is a technical one, so I focused the question on that. Hopefully, it will get a better reception.
    – fixer1234
    Dec 4, 2015 at 20:31
  • Thanks for taking the time to edit the question (I prefer this version) and leave the comment. I appreaciate it. I seem to have over-emphasized explaining my specific situation (buying the adapter) and tried too hard to show the relevance of the question for me. I'll stick to the techincal side next time!
    – Heihej
    Dec 4, 2015 at 20:45

1 Answer 1


First of all, your question's title is misleading, because your question is limited to Mini DisplayPort and USB as sources. If your question were general, the answer would be different.

The concepts of the two solutions are as different as they can be.

  • Mini DisplayPort to HDMI adapters will mostly be cables which map pins. This means that this is a passive device which just maps one connector standard to another. Your computer's graphics card will be used.

  • USB to HDMI "adapters" are really USB graphics cards which require a driver. The computer will transfer the resulting image data as video buffer differences (or similar) to the graphics card. I've researched some benchmakrs for another use case and there is a significant performance drop. It's alsways okay for office work but you should check test reports of specific devices against your requirements. The video modes supported by the USB graphics card may be different from those in your computer. That may be good or bad.

Having said that, it's questionable why you would want to go for the USB solution in your case. The data transfer on USB as well as the power supply for the external graphics card via USB will at least lead to shorter battery life and will also mean some work for internal buses.

The USB solution may be the best choice if you're dissatisfied with your computer's graphics card and don't intend to play 3D games.

  • Thanks for the answer, I wasn't aware how any of the adapters work.
    – Heihej
    Dec 4, 2015 at 17:50
  • Sorry for the misleading title, I was trying for a balance between a general question and explaining my situation. It seems that an answer to the more general question would be more helpful for others (and more interesting), but I read that the question should be made specific to my situation. Wouldn't the situation be similar even for different ports, the contrast being between passive devices and those requiring a built-in driver?
    – Heihej
    Dec 4, 2015 at 17:56
  • Actually, for the general case, there are also different solutions, where you provide an analogue signal and get a digital one out, or vice versa, although these are dying (the last analoge standard which we will see for a bit is VGA I guess), so those solutions are boxes which convert one video signal to another and that's a totally different story, also regarding quality. And since you mentioned quality in your Q title, mentioning this third approach would make a huge difference.
    – Run CMD
    Dec 4, 2015 at 18:10

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