Metspitzer wrote:
> On Thu, 21 Jun 2012 18:14:20 -0400, Metspitzer <(E-Mail Removed)>
> wrote:
>
>> I was using an old VGA monitor as primary (VGA connector). I was
>> using an LCD monitor for a second monitor (DVI). It worked fine.
>>
>> I replaced the VGA monitor with another LCD monitor using a HDMI.
>>
>> When I try to extend the second monitor nothing happens. The existing
>> LCD monitor will not work. When I go back to the settings the setup
>> can see the second monitor but the "extend" check box is unchecked.
>>
>> I have an ASUS M4A79XTD EVO mobo.
>
> Since everything else failed.........I read the instructions. It says
> HDMI + DVI not supported.
> Never mind
"HDMI + DVI not supported."
Bingo.
Some of these chips, they only have one digital output. And you
can either use DVI or HDMI, but not both at the same time.
That has also happened on a couple models of sub-$50 video cards.
The cards have multiple connectors on the faceplate, but a
couple of them can't be used at the same time. You have to
read the customer reviews on Newegg, for confirmation of
such design stupidity. The product description may
conveniently forget to mention it. Either the GPUs were
rejects, or they were doing cost saving, by not adding a
TMDS transmitter to make another independent interface.
Some GPUS, they have auxiliary digital busses for output. When
you want a particular flavor of connector for the video card
faceplate, you add a chip. So you might add a "TV chip", to go
from digital bus to Composite or S-video. Or a "VGA chip", to
convert from the digital bus to VGA. Or a "TMDS transmitter"
to make a separate HDMI or DVI. Such a scheme adds flexibility,
but at the price of having to add chips to the design.
As for the folks at Asus, they haven't always been the best
at addressing this in the user manual. Many of the early
multiple output motherboards, made no mention of any
restrictions. The users had to figure it out.
Paul
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