VGA to DVI adapter - image quality??

[photoamat]

I am in the process of purchasing a new geforce 6600 gt graphics card. I was going to buy the lead tek geforce px6600gt tdh. But I saw that they have one dvi and one vga output. If wanted to use two lcd monitors, and if choose to use the vga to DVI adapter, will i see any difference in the image quality between the two monitors( one connected directly to DVI, and another connected VGA to DVI adapter)? Your help is greatly appreciated. Also if possible please point me to links with this info on the net.

thanks.

 

[YOyoYOhowsDAjello]

A VGA to DVI adapter is going to cost about the same amout as that whole card I think.

example

 

[Auric]

What do you mean "the" VGA to DVI adapter, implying such is included? Dual DVI cards usually include the opposite which are cheap. Presumably at least one of the LCD monitors has a VGA input too so an adapter would be unnecessary. In any case, if they are both DVI it would be best to simply get a dual DVI card. The quality difference should be noticeable but not necessarily significant. More significant is the functional differences: lack of certain options and the necessity of manual adjustment with VGA.

 

[Peter]

There is no VGA->DVI adapting, period. You'll be on the analog VGA signal, and yes, this looks noticeably worse than DVI.

 

[YOyoYOhowsDAjello]

Originally posted by: Peter
There is no VGA->DVI adapting, period. You'll be on the analog VGA signal, and yes, this looks noticeably worse than DVI.

Yes there is

 

[Peter]

No. You can't "adapt" the analog VGA signal back to digital DVI. You can resample, store, and regenerate into a digital signal. That's what the (rather huge) DSP board inside the panel display does.

 

[YOyoYOhowsDAjello]

Originally posted by: Peter
No. You can't "adapt" the analog VGA signal back to digital DVI. You can resample, store, and regenerate into a digital signal. That's what the (rather huge) DSP board inside the panel display does.

Ok, I was meaning the vague sense of the word as in you can plug in a DVI monitor like the OP wanted to a box that will convert a signal from VGA. I guess I don't know the technical definition of "adapt".

Clearly the OP should just get a dual DVI card though if he wants to hook up two DVI LCDs, so I'll be quiet now.

 

[blinky8225]

If the monitor has a DVI-I port I think you can. The signal will still be analog of course, though.

 

[photoamat]

I don't know the technical details of the adapters. But the leadtek site and the internet retailers who sell cards say that there is a vga to dvi adapter included in the package. I was skeptical about what they did and what the quality was. I was also skeptical about the quality it would output. In any case I think I will try and get the xfx 6600 gt which has two dvi out.

thanks for the answers.

 

[egkenny]

All the cards I have seen with a digital port have a DVI-I connector. Outwardly it looks like like a DVI port but has the extra pins for analog output also. Normally it is used with the DVI port on an LCD monitor. The include adapter will simply access the extra analog pins to allow hooking up a VGA monitor.

Examples I have worked with are the ATI 9800 Pro and the Nvidia FX5900. Each has two video connectors. The first connector is VGA only one. You can either hook it up to either a CRT or LCD using their VGA connectors. The second is a DVI-I port. You can either directly hook an LCD monitor directly to it's DVI connector or treat like a second VGA port by using a DVI-I to VGA adapter. Many cards include this adapter.

If the digital port on the graphics card is a plain DVI one then it can only be connected to LCD monitors since it has no analog capabilities. DVI-I ports are more common and allow for the most flexibility.

There are some cards that no standard VGA port at all but have dual DVI-I ones. An example is the Nvidia Quadro FX1100. This contrasts to the Nvidia Quadro FX500 which has one VGA port and one DVI-I one.

 

[YOyoYOhowsDAjello]

Originally posted by: photoamat
I don't know the technical details of the adapters. But the leadtek site and the internet retailers who sell cards say that there is a vga to dvi adapter included in the package. I was skeptical about what they did and what the quality was. I was also skeptical about the quality it would output. In any case I think I will try and get the xfx 6600 gt which has two dvi out.

thanks for the answers.

The basic deal is that there's an adapter that turns a DVI port in to a VGA. It will not work the other way (turn VGA to DVI). DVI-I to VGA is incredibly easy because the VGA signal is part of the DVI-I output, but you can't get DVI back from VGA without a really expensive product like the one I linked to.

So, if you want dual DVI, you should get a dual DVI card.

If you get a single DVI card, you can run it as VGA and DVI or two VGA, but not two DVI.