'DVI' vs 'VGA with adapter'

L

lzqtiancai

Limp Gawd
Joined
Jan 21, 2011
Messages
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yesterday when I was setting up multi monitor, I ran out of DVI cables, So I used a vga cable with a dvi to vga adapter to connect to my gtx 460, and then just connect to the monitor via vga, since my monitor has both vga and dvi. Now I am just wondering

would the quality of "DVI" and "VGA with dvi adapter" be the same?
I personally didnt notice any difference.
 
Personally I prefer DVI over VGA. It works well with LCD monitors (if that's what you're using.) and DVI usually allows for sharper images (don't know about the image quality). Plus if you're into HDCP, DVI allows for content to played on a HDCP certified monitor.
 
It matters for higher resolutions. at 1680x1050, the differences are hard to find. At 1920x1200, it's much more apparent.
 
Everyone has a different ability to discern quality images and/or sound. Personally, when I use adapters to go from DVI to VGA, I see the screen as grainy. The adapter is converting a digital signal to analog, then the monitor is converting it back to digital. Picture quality is lost. VGA worked well with analog monitors, but gone are those days for most people. Get on newegg and spend the $12 for DVI cables.
 
Where is "shop over here" for a $3 shipped DVI cable? I'd like to know.
 
It depends on the monitor. You SHOULDN'T be able to notice the difference, but if the monitor has a crappy VGA implementation then you will. For example, my monitor, a SOYO Topaz S, looks just as good over VGA as it does over DVI (probably because it seems to be VGA by default, with a DVI port stapled on), so I stuck with that since I could get a higher refresh rate over VGA.
 
SRT8 said:
Everyone has a different ability to discern quality images and/or sound. Personally, when I use adapters to go from DVI to VGA, I see the screen as grainy. The adapter is converting a digital signal to analog, then the monitor is converting it back to digital. Picture quality is lost. VGA worked well with analog monitors, but gone are those days for most people. Get on newegg and spend the $12 for DVI cables.
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Actually, the adapter isn't converting anything. DVI-I and DVI-A supply analog signals for monitors with analog only inputs. The adapter just passes those signals through to the correct VGA pins so the monitor can use them. It's no different than having an actual VGA port on the video card. If the video card only has a DVI-D output (none do that I know of), then you wouldn't be able to use an adapter at all.

And converting a digital signal to analog does not necessarily mean there is a loss in signal quality. It's simply mapping each bit combination to different voltage levels. Converting back is the reverse. Now if it were originally an nalog signal to start with, there would be significant loss of information... but that's not the case here. The lost of quality is due to noise introduced by either cheap cables or poor quality conversion in the monitor itself.
 
ryan_975 said:
Actually, the adapter isn't converting anything. DVI-I and DVI-A supply analog signals for monitors with analog only inputs. The adapter just passes those signals through to the correct VGA pins so the monitor can use them. It's no different than having an actual VGA port on the video card. If the video card only has a DVI-D output (none do that I know of), then you wouldn't be able to use an adapter at all.

And converting a digital signal to analog does not necessarily mean there is a loss in signal quality. It's simply mapping each bit combination to different voltage levels. Converting back is the reverse. Now if it were originally an nalog signal to start with, there would be significant loss of information... but that's not the case here. The lost of quality is due to noise introduced by either cheap cables or poor quality conversion in the monitor itself.
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I find it amazing how much dis-information there is on the Intenet from folks that actually mean no harm, but JUST DON'T KNOW wtf they are talking about, or are just imagining things.

This thread is a perfect example.

Thanks for your sanity and energy to try to set some things straight.
 
SRT8 said:
Everyone has a different ability to discern quality images and/or sound. Personally, when I use adapters to go from DVI to VGA, I see the screen as grainy. The adapter is converting a digital signal to analog, then the monitor is converting it back to digital. Picture quality is lost. VGA worked well with analog monitors, but gone are those days for most people. Get on newegg and spend the $12 for DVI cables.
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I'd say that it depends more on the monitor than on the person. A lot of monitor manufacturers use cheap components for their VGA input (if they have DVI) and therefor there can be quite large differences.

But if it done right I doubt you'd see any difference at all, it's not at all certain that a digital->analogue->digital conversion implies worse picture quality. All signals are analogue and has to be treated as such.

Also, the adapter doesn't do any signal conversion at all, DVI-I contains both digital and analogue pins and all the adapter does is rewiring the analogue pins to the corresponding pins on a VGA

EDIT: Gah, guess I missed a few posts while I forgot to post this :p
 
J Macker said:
Where is "shop over here" for a $3 shipped DVI cable? I'd like to know.
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someone is selling it on here(hardforum) for 3 dollars shipped a piece. I cant tell you who exactly b/c Im going to buy it in couple days, I dont want you buy it before me ;)
 
lzqtiancai said:
what kind of difference are you saying here?
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The kind of difference where you use what you got until you can afford to get a DVI cable. then you switch it out. With any converter you add connections, and connections in video are the weakpoints.

It will probably be ok for now, but next time your in a electronics store spend the $5 to buy a DVI cable.
 
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