Hi, Frederic,

I was testing similar situation on GeForces more than 2 years ago (I left
the building in the meantime) and honestly don't remember if we have found
'an always working' recipee for this problem. All I remember we were
somehow able to use multiple cards with multiple monitors but honestly I am
not sure if this was just luck with drivers or we did some extra tricks (we
tried several workarounds back then). This problem is probably related to
Windows DWM screen update scheme vs NVidia optimizations and Windows 7
design that primary card renders all OpenGL contexts so second card is
practically not used. I could be wrong but I believe we had most success
with NVidia surround where we set up single Window spanning all monitors
and this window was split into 3 or 4 viewports matching particular
monitors.

So I really don't have a solution but would recommend to test various
options and select the best one.

- Test single card dual monitor output vs dual card sli dual monitor vs
dual card / dual monitor. I remember that after this test we realized it
does not make sense to buy
second card which is practically not used. SLI mode seemed to not bring
more performence in our scenarios (this may vary for you of course). So we
realized that unless we do not want to use more than 2 monitors we will not
buy another card. And even with more monitors it would make sense to
buy powerful card as primary and weak one as secondary adapter because it
will be practically used as passthrough for graphics rendered on first one.
For Surround mode it may be  neccessary to use the same cards though,
(don't remember exactly). Above problem only affects GeForces. Quadros
provide extension which can be used to assign GPU to window. h
ttp://developer.download.nvidia.com/opengl/specs/WGL_nv_gpu_affinity.txt<http://developer.download.nvidia.com/opengl/specs/WGL_nv_gpu_affinity.txt>
Unfortuantely
NVidia chose to not provide it for GeForces. I also believe that Radeons
have introduced similar extension a year or two ago.

- Do above tests with NVidia surround.

- Try playing with NVidia control panel settings (threading optimization /
swap method)

And certainly must have options are:
- Aero off / fullscreen mode to avoid DWM quirks

HTH,
Wojtek Lewandowski

2012/5/20 Frederic Bouvier <[email protected]>

> Paul,
>
> I see the same issue with 3.1.2
>
> Regards,
> -Fred
>
> ----- Mail original -----
> De: "Frederic Bouvier" <[email protected]>
> À: "OpenSceneGraph Users" <[email protected]>
> Envoyé: Dimanche 20 Mai 2012 10:10:42
> Objet: Re: [osg-users] Multiple GPU/monitor issue on Windows 7/NVidia
>
> Hi Paul,
>
> I should have stated that I am using OSG 3.0.1. Is there a fix in a
> development release ?
>
> Regards,
> -Fred
>
> ----- Mail original -----
> De: "Paul Martz" <[email protected]>
>
> I thought this was an old issue already fixed. Are you saying this is still
> occurring on the current OSG trunk? What versions of OSG have you tested?
>    -Paul
>
>
> On 5/19/2012 9:03 AM, Frederic Bouvier wrote:
> > Hi,
> >
> > I am pretty sure it has been discussed before, but I am unable to
> retrieve the
> > right thread, so ...
> >
> > I have a dual card setup, each driving a single monitor. When I start
> osgViewer,
> > the viewer span on both screen, an initial image is displayed on both
> too, but
> > only the primary display is updated when I change the camera view with
> the
> > mouse. Clicking on the frozen screen and then on the live screen update
> the
> > image on the frozen screen but only for one frame.
> >
> > I have the last WHDL NVidia driver. Cards are 2 GF GTX470 and I tried
> with and
> > without SLI enabled. The same problem occurs in a multiscreen setup of
> FlightGear.
> >
> > Any idea ?
> >
> > Regards,
> > -Fred
> >
> > _______________________________________________
> > osg-users mailing list
> > [email protected]
> >
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> >
> >
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