Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Some video adapters have both DVI and VGA outputs. For a two screen configuration I could attach a VGA to DVI adapter to the VGA output, and have both screens attached with a DVI cable.

Would the video adapter detect this and transmit digital video instead of analog?
Does it depend on the specific video adapter model?

share|improve this question
up vote 4 down vote accepted

Well there are two ways to do that:

  1. VGA to DVI Adapter: With a simple VGA to DVI Adapter, BUT the signal will not be digital! Because the DVI specification contains also wires for the analog signal, there are plenty of simple adapter for just some dollars. So if your Screen is able to use these analog signals on the DVI cable it may work. But remember you then have a DVI-A (analog)
  2. VGA to DVI Converter: There are external active converters of analog to real digital signal, but they are a bit more expensive. Then you would have a real DVI-D (digital) signal.

Maybe read the good wikipedia article explaining the basic technical details.

share|improve this answer
The converter will not improve on the loss of video quality due to using VGA analogue signals, but it may prevent the "shadow effect" sometimes visible when using a VGA analogue signal throughout the cable to the screen – Jonathan Jul 12 '13 at 13:17

No. VGA only outputs the video signal as Analog only.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.