I experience severe frame drop with the multi monitor setup used for my application. I have 2 nVidia graphic cards, with one VGA and one DVI output each. I use three of the outputs (It is not relevant if it is 2xVGA + DVI or 2xDVI+VGA). And I have a window with NSOpenGLView. I have no problem running at up to 60-70fps, as long, as the window is only on monitors connected on the same video card. Whenever the window occupies monitors connected on different cards the frames drop to 20-24 and WindowServer starts crunching 50-55% of the CPU.
I haven’t tried yet with fullscreen, as I can’t make the application go fullscreen on anything else than the main screen (the one with the menu bar).
I haven’t tried with GLUT either, yet.
The machine is Hackintosh, as I have yet to finish a project that would finance a real Mac Pro :D The cars are fully recognised and supported (Quartz Extreme, QuartzGL, Core Image, etc), identical Gigabyte branded 9800GT 512MB
So, I was wondering what is causing the frame drop. Is there anything specific about having an OpenGL window occupying monitors on different cards? Am I able to do anything about that?