Charlie said:
I presently have two monitors, and am wondering if it's possible to
run three. My motherboard (Foxconn P45A-S) seems to support dual video
cards. I have a Gigabyte GV-NX96T512HP (GeForce 9600 GT 512 MB) card
now. Is it possible to just add another card to drive the 3rd monitor?
will Windows (I have Vista, but am thinking of going to 7 Pro)
recognize the 3rd monitor automatically?
This is a picture of a four monitor setup.
http://img197.imageshack.us/img197/6043/extendednvidia128080012.gif
That is a screenshot. The configuration consisted of a 1280x1024 monitor,
800x600 monitor, 1280x1024 monitor, 640x480 monitor. Two FX5200 video
cards were used, one was a PCI version, the other was AGP. Each card
supported two monitors. The PCI card is a little on the slow
side, due to the bus bandwidth limit. Your PCI Express slots
wouldn't have an issue with that.
At that time, I only owned one monitor, and the other three monitors
were simulated with hardware tricks (terminator resistors on some
connectors). But that didn't prevent me from taking a screen snapshot of
the entire set.
You can see from that picture, it would help if all the monitors had the
same height, as the desktop has some "black" areas.
Now, one thing you'll notice, is the task bar is only on the left most
monitor. I don't know all the details of getting it across the whole
thing. There may be an issue with spanning the task bar across all four
monitors (because there are two video cards). You may be able to span
it across one or two monitors, but when the second video card is involved,
I'm not sure what happens then. Since my monitors couldn't all be
set to the same resolution, I couldn't test that aspect of it.
Another thing that happened to that demo. In the picture, you can see
the Display control panel, showing 2-1-4-3 for the monitor numbers.
Half way through my testing, the screen "blinked" on its own, and
the next time I looked in the Display control panel, it read out as
4-3-2-1. The two video cards "swapped sides" for some reason. That
didn't exactly impress me.
But that was all part of the fun. I wanted to see whether you could
span four monitors across, and it seemed to work. But there are a
few unanswered questions, as to whether you'd be in control of
all aspects of operation that way.
*******
Video cards in the past, supported one monitor, or later two monitors
via "dual head". At one time, the "dual head" cards weren't completely
symmetric - one connector had more DAC bandwidth than the other. Cards
were pretty goofy back then.
Dual head has existed for years, without changing much.
Recently, ATI brought out new video cards featuring Eyefinity. That
supports up to six monitors with a single video card (and not even
requiring multiple GPUs - that is with one GPU). The trick to that
scheme, was restrictions on the connector types. Two connectors are
"conventional", of the six. They could be DVI-I connectors for example,
able to support DVI or VGA monitors.
The other four connectors are DisplayPort. That is a digital standard.
DisplayPort is pretty useless by itself, because the cheapest of LCD
monitors have only DVI-D on them. Some of the higher end ones,
may have an actual DisplayPort connector (as well as HDMI, DVI, or
even VGA).
DisplayPort can be converted to other standards. One conversion is
passive, so the adapter is cheap. Several other types of DisplayPort
conversion are "active", and involve the use of a chip inside the
adapter. Those would not be quite as cheap, and a power source may be
part of the package.
You can likely find an article around somewhere, which lists all
the arcane restrictions.
http://en.wikipedia.org/wiki/Eyefinity#Multi-display_technologies
http://www.anandtech.com/show/2833
Picture of a 6950 from ATI with six monitor connectors... $324.99
http://images17.newegg.com/is/image/newegg/14-121-431-Z01?$S640W$
For $65, you can get goofy Eyefinity cards that support three
monitors, but the connectors are all different types.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102875
*******
Another way to drive more monitors, is with Matrox screen splitters.
These would take a video card output of 2560x1024 and make two
1280x1024 monitor signals with it. That is an active technology
and relatively expensive compared to buying a cheap video card
to add a couple monitors. There are three or four versions
of these adapters (digital, analog, drive two or three monitors).
Sufficient output resolution must be available, to make it work.
Matrox DualHead2Go Digital edition
http://www.newegg.com/Product/Product.aspx?Item=N82E16815106016
+------------------+ +-----------+ +-----------+
| 2560x1024 | ===> | 1280x1024 | + | 1280x1024 |
| | | | | |
+------------------+ +-----------+ +-----------+
Your video card thinks it is driving a single monitor on one
of its connectors. The two output connectors end up with half of
the image each. Since the input was digital to begin with,
there is no loss in the conversion. I don't think HDCP would be
supported with this scheme. And there are probably a few more
details, which you might find on the Matrox site.
http://matrox.com/graphics/en/support/gxm_main/
Using your existing video card, you'd drive one monitor directly,
and use the second connector via the Matrox product, to drive
two more monitors.
In many cases, a second video card would be cheaper. That
scheme is mainly intended for something like a laptop. With
a desktop, you have more options.
*******
A gallery of multi-monitor configurations exists. This site
hosts pictures people have provided, of using multiple monitors.
The notes sometimes mention issues with installing drivers, or
perhaps a certain driver installation order. I think you'll
get a kick out of this site.
http://www.realtimesoft.com/multimon/gallery_browse.asp?ID=954&date=desc&nummon=false&mon=desc
HTH,
Paul
