SLI and TrackIR horizontal tearing ?

[Tinribs]

When I enable sli I get horizontal tearing i dont get this in any other games, switch it off and the game runs fine I thought it was just when I was using my TrackIR but my top hat views are the same.Does anyone know whats causing this ? and is anyone else having the same problem? Its not really too much of a problem I just have to remember to switch sli on and off.

xp32bit pro with directx 10 {was the same using 9}
striker extreme 780i chipset
intel q9400
crucial 2gb ram 800mhz
2x asus gts 250 DKs 512mb
TrackIR 4 with 5 software {same thing happens with 4 or 5 software and track clip and track clip pro}
My pc has all the latest drivers for everything and nothing is overclocked,any help would be great,
thanks,
         shotdown.

[gpwurzel]

Pretty sure I remember someone posting that sli disables anti aliasing, which will be causing the tearing you are seeing. Also remember someone posting a way to force AA on with sli.

Hope you get it sorted mate,

Wurzel

[Skuzzy]

SLI disables vetical sync, which can cause tearing in the graphics.  Nothing we can do about it.  As far as I know it is a design limitation within the SLI architecture.

[Tinribs]

Thanks for your usual quick reply skuzzy (do you ever sleep?) its good to know that nothing is wrong at my end anyhow,do nvidia know about the problem? I imagine they do,if nothing can be done about it why dont they have a way of switching automatically in the ntune profiles? as far as i can figure they dont.
once again thanks for the help,
                                         shotdown.

[Skuzzy]

As it was/is a design decision on the part of NVidia, I am pretty sure they know about it.  Seems SLI was designed for use with first person shooters in mind and not much anything else.

Of course, if the frame rate is low enough, the graphics tearing would not be an issue.  It only happens when the frame rate exceeds the monitor vertical sync rate by a good margin.

It is ironic.  A badly coded game, which runs poorly on a PC, is really what SLI works best with.

[Chalenge]

Skuzzy I noticed the SLI problem is true in XP and not so in Vista (at least for 64 bit) and I dont know what the difference would be in the SLI profiles but after several driver updates in Vista the SLI and vsync have always played well together on Vista but my XP machine has to have Single GPU selected and otherwise they are identical computers. I thought it worth mentioning anyway.

[Tinribs]

well thats intersting chalenge,does anyone know if xp64bit works in sli? I would consider upgrading to that if it does but I wouldnt touch vista with mine or anyone elses barge pole.
thanks,
shotdown