DVI vs VGA?

Question

What are the benefits of DVI over VGA? Please provide sources if possible. Thank you

Thorson: AM I right in saying an analog cable converts the digital data outputted from a computer into analog, into the monitor, and then the monitor converts it back to digital? If yes, why the need for an analog cable if the monitor is going is reading off digital data anyway.

Answer 1

As stated above VGA is a legacy from analog CRT monitors.


While DVI does have better noise immunity, the real advantage is that the signal does not need to be re-sampled.

The analog signal is sent as a step-wave. Plateaus of signal where the pixel is at one level, then a steep slope to get to the level of the next pixel. The problem is is that the steeper the slope the more EMI interference you produce and the more power you need to drive the signal, so there can be quite a bit of time where the slope eats into the size of the plateaus.

But the LCD panel has to sample the signal to convert it back to digital. It needs to sample on the plateaus to get an accurate level. But there is no pixel clock sent with the VGA signal to say where those plateaus are. So the monitor has to do a best guess. This is the auto setup. Most times it works reasonably, some times it does not and all the text o the screen looks fuzzy or jittery.

Since DVI is sent as a digital signal it dose not suffer from the need to resample and so produces a very stable picture.

Answer 2

Dvi Vs Vga

Answer 3

VGA is an older standard that was created before the use of LCD monitors. The older CRT's were analog, so it made sense to have an analog signal driving them. The VGA standard uses three wires that transmit the level of Red, Green and Blue, the monitor combines these to create all of the colors of the spectrum.

DVI also uses the three primary colors, but the signal is sent in a digital fashion. As modern LCD monitors are digital devices this is more suitable, and the signal is not degraded by converting it to analog only to reconvert it to digital within the display.

DVI monitors, being digital, are not subject to interference as analog VGA monitors are. This also means that if you need to you can run an extension cable to a DVI monitor with better results, doing this with VGA will produce "ghosts" and other distortions,especially at higher video resolutions.

The only source I can provide is that I used to be an electronics technician and for a few years serviced (analog VGA) monitors exclusively.

Answer 4

VGA is analog , a and guess what, the computer talks digital!

so VGA needs to be converted before its displayed, that way it loses quality


DVI is all digital, no conversion, no data/quality loss!

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Its the Video Card that does the converting,