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Old 01-19-08, 02:05 PM   #1
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Join Date: Jul 2005
Location: Munich
Posts: 910
Default Triple-Head Setup without Xinerama?


I'm running a triple-head setup (3x 1600x1200) off two nvidia
cards (2x 7800GTX, later 2x 8800GT) for more than two years, now.
In order to form a single desktop screen with two cards, it
is necessary to use Xinerama. However, my experience is that
Xinerama is always a good source of problems, i.e. reduced
stability, Beryl not working, artefacts with X-Plane at certain
weather conditions and mouse pointer missing in UT2K4.

So I'm looking into another solution in order to get rid
of Xinerama altogether!

An interessting product for this would be the "Matrox TripleHead2Go
Digital Edition" that splits one output into three outputs, but
this device is limited to 3840x1024 (where i need 4800x1200).

The alternative would be the "DualHead2Go" counterpart, which can
do up to 3200x1200: through this box, two displays could be connected
to first output of a video card and the third displays could be connected
to the second output. The two outputs could then operate in twinview
mode in order to operate as a single big 4800x1200 screen.

  Videocard          Splitter      Displays
  ________             ____
          |           |    |
          |           |    +------> LCD #1
    DVI-D +---------->+    |
          |           |    +------> LCD #2
    Out   |           |____|
    DVI   +-----------------------> LCD #3

So this sounds like a feasible solution, but there are a number
of obstacles:

First, i couldn't figure out by a 100% if the Matrox box works
with Linux. Some googleing surfaced that at least the "native
resolutions" should works where i assume 3200x1200 is one of them?
OK, this is not exactly an nvidia thing, but is strongly related to
the next question:

Can the first DVI output of a 8800GT generate a 3200x1200 resolution?
Officialy, the maximum resolution (width-wise) is 2560x1600.
3200x1200 requires less bandwidth - so it might work? Are the 2560
pixel a hardware limit?

Third, since the above described solution would only require a single
videocard, my second 8800GT would be rendered useless, unless it
would be possible to run twinview in SLI mode (which is currently not
possible, AFAIK). Are there any plans to provide twinview-SLI support?
(However, this point is not critical.)

Any feedback is highly appreciated!


JaXXoN is offline   Reply With Quote