Viewsonic VX715: No DVI output, why?

[fow99]

Just got my Viewsonic VX715. Hooked up with my Gainward FX 5700 and can
only get output from analog output, which doens't look too good. Is there
anything else I need to configure? I bought the "Belkin Cable/Pro Digital Video DVIM-M Sgnlink 3m"
with it. That's the right one isn't it?

 

[Peter]

Welcome to the wonderful world of NVidia's DVI output that doesn't.

 

[fow99]

Doesn't work? You mean it is the graphics card? How's that possible?

 

[Peter]

NVidia's graphics chips have an internal TMDS transmitter chip just as ATi's do. (TMDS is the signal type transmitted over the DVI cable.) While ATi's actually works very well across the full frequency range all the way up to 165 MHz (as needed by the big LCDs like yours), NVidia's have shown quite a massive signal quality issue when the frequency goes above 120-140 MHz - in every single DVI signal quality review I've seen. You aren't the first to plug in a display that doesn't even recognize a signal in all that garbage.
Some card makers have resorted to putting a discrete TMDS transmitter chip on - these work too, then.

 

[fow99]

Thanks. I managed to get DVI output in the end. I didn't know that I need to
configure the driver.

 

[Peter]

sooo ... care to tell us what exactly you did?

 

[fow99]

Originally posted by: Peter
sooo ... care to tell us what exactly you did?

Not much. Initially when I posted the problem, I was in Linux. And then I figured it would
be easier to identify the problem under Windows. So I rebooted but found the same
problem. And then I did some searching in the Nvidia control panel and found an option
to turn on digital output and everything is find. I went back to Linux and did similiar thing
(through editing xorg.conf) and it was working fine too. One thing I did notice is that in
general, the display quality in Windows is higher.