Max Res through DVI?

V

vizx

Weaksauce
Joined
Jan 18, 2006
Messages
103
when max res is listed under the specs for a video card, it's the max res for VGA, correct?

how do you find out the max res for DVI on a video card?

i need a temporary AGP vid card upgrade before i go PCI express/dual core in January...

i just bought a sony sdmp-234 23'' lcd and i need an AGP card that will run 1920x1200 through DVI...

i was thinking of this one...

http://www.newegg.com/Product/Product.asp?Item=N82E16814127219

i wanted to know the max res through DVI on it....
 
Well, I could have sworn that there was limitation with the single-link and not dual-link cabling. I've always believed that if you ran a dual link DVI cable that it would be able to support the higher resolutions at higher refresh rates. I'm sure that that 7600GT should support it too. Maybe someone can give a more detailed/complete explanation.
 
Just as a reference, even my 'old' XFX 6800xt AGP card will run 2560x1600. If you want to be running resolutions over 1920x1200, get a dual link DVI output on your card. Pretty much all the newer mid range to high end cards have it.
 
Single link DVI can go up to about 1920x1080 or whatever 2.6 Mega-Pixels is. Dual link DVI is required to run over that.

For example, you need a dual link DVI capable card and cable to run a Dell 3007WFP or Apple's 30" Cinema display. In analog mode, these restrictions are not present. My analog CRT can do 2048x1536 all day on just about any card.
 
RAMDAC restricts the maximum resolution and refresh rate of your analog outputs.

Most video cards have a 400 MHz RAMDAC, which, after about %20 signaling overhead, means a maximum resolution of around 2048x1536 @ 85 Hz. You could probably do higher, but such monitors do not exist, so no manufacturer advertises better.

Mind you, VERY FEW analog outputs have the bandwidth to display this without signal distortion, so in my mind it's not worth it. I typically keep my analog monitors at 1280x960 for text, and 1600x1200 for image manipulation for this reason (I love sharp text).

For DVI, the raw data rate CAN handle 2.6 megapixels at 60 Hz, however the maximum resolution also has to take into account around %20 signal overhead, so you really get around 2.1 Megapixels resolution. This means you can do 1600x1200 or 1920x1080 at 60Hz.

Dual-link DVI can handle double this (~4.2 megapixels at 60Hz), and potentially even higher, because the signaling rate is not capped at 165 MHz as it is on single-link devices.
 
A single DVI link is bandwidth limited to 165MHz.
This is good enough for 1600x1200 with any graphics card that supports the resolution.
Recent cards and drivers support 'reduced blanking' for higher res modes, allowing 1080p modes to function on a single DVI link.

The 7600GS will work fine.
 
defaultluser said:
RAMDAC restricts the maximum resolution and refresh rate of your analog outputs.

Most video cards have a 400 MHz RAMDAC, which, after about %20 signaling overhead, means a maximum resolution of around 2048x1536 @ 85 Hz. You could probably do higher, but such monitors do not exist, so no manufacturer advertises better.

Mind you, VERY FEW analog outputs have the bandwidth to display this without signal distortion, so in my mind it's not worth it. I typically keep my analog monitors at 1280x960 for text, and 1600x1200 for image manipulation for this reason (I love sharp text).

For DVI, the raw data rate CAN handle 2.6 megapixels at 60 Hz, however the maximum resolution also has to take into account around %20 signal overhead, so you really get around 2.1 Megapixels resolution. This means you can do 1600x1200 or 1920x1080 at 60Hz.

Dual-link DVI can handle double this (~4.2 megapixels at 60Hz), and potentially even higher, because the signaling rate is not capped at 165 MHz as it is on single-link devices.
Click to expand...

The top resolution theoretically supported by dual link DVI is 3840x2400 or 9.2 mega pixels.
 
As long as the TMDS sender in the DVI output is good, single link DVI can (in theory) get to 1920x1200@66Hz or 1920x1080@75Hz. In practice I have run a Dell 2407fpw at 1920x1200p63.01 over single link DVI from a lowly Radeon 9200. Plus
I have helped DTV forum acquaintances get the Pyrod 3711 37" LCD TV up to 1920x1080p72, and others have run an Acer AT3705-MGW 37" LCD TV at 1920x1080p74.4 over single link DVI.

See here for more commentry and links.

Adrian
 
will running two cards in SLI change their max resolution?

I have 2 Geforce 6800XT (XFX) and I'm considering getting a 30" Dell LCD. I don't believe they will be able to run this even in SLI (I don't believe they have dual link DVI) but I figured I would ask.

Any ideas?
 
samw5 said:
will running two cards in SLI change their max resolution?

I have 2 Geforce 6800XT (XFX) and I'm considering getting a 30" Dell LCD. I don't believe they will be able to run this even in SLI (I don't believe they have dual link DVI) but I figured I would ask.

Any ideas?
Click to expand...

SLI won't change their max resolutions.

Just find out, from the MFR, if the card has a dual-link DVI. If it does, you're good to go. If not, no joy. But....i think...if you are planning on buying a $1300 monitor, you should consider getting better video cards to drive it anyways.
 
Samw5, Your video cards can run a max VGA resolution of 2560x1600 but the max resolution you can get via DVI is 1600x1200 as they single-link DVI ports on that video card. To run a resolution greater then that you will need a video card will dual-link DVI ports. Also when running SLI it will not change the max resolution of the video cards but allow for a better image and performance at higher resolutions. If you have any other questions please let me know.

XFX Support
 
What about 1680X1050 widescreen? Would that require a dual-link cable or is a single sufficient? Since the total pixel count is actually lower than 1600x1200 I assume single is sufficient. Yes?
 
XFXSupport said:
Samw5, Your video cards can run a max VGA resolution of 2560x1600 but the max resolution you can get via DVI is 1600x1200 as they single-link DVI ports on that video card. To run a resolution greater then that you will need a video card will dual-link DVI ports. ...
Click to expand...

XFX Support, your comments are very surprising.

What you are saying is totally contrary to advice given to me by the tech guys at Silicon Image (the company that developed the core technologies for DVI). It is also totally contrary to my experience, and many other users experience, of using DVI on 1680x1050, 1920x1080, and 1920x1200 monitors (see the link in my post #8).

Or does XFX limit its DVI links?
 
Dan_D said:
The top resolution theoretically supported by dual link DVI is 3840x2400 or 9.2 mega pixels.
Click to expand...
Single-link is 165 MHz while dual-link is 330 MHz, thus the bandwith is doubled, not 4x as you suggests.
 
You must log in or register to reply here.
Back
Top