3x NVidia Quadro NVS 450 => 12 screens

OpenGL
1

I have a machine at hand, with a Core i7 CPU, and 3 NVidia Quadro NVS 450 cards, each connected to 4 1920x1080 LCD displays.

I need to run a simple but smooth 60Hz OpenGL animation on this system.

For now, I’m at loss, I tried :

  • creating a single GL window for the whole 8K x 3K desktop ; just using glClear on this very slow
  • creating a window per screen, each with its context, once again just using glClear is slow (but better than above)

Does anyone have experience to share with this kind of setup ? Such as achieving 60Hz display of anything on the multiple displays ?

Cheers,

Nicolas.

2

Hi,

The Quadro NVS 450 is a really slow chip… you can’t expect great performance. When you say “slow”, you do mean that do don’t even have 60Hz with only a glClear?

Your framebuffer worth 100 MB… 6GB/s @ 60Hz (hopefully dispatch across all cards but I believe copied on all cards) for a maximum of 11GB/s… It might be tricky quite quickly.

12 screens… nice!

3

Yep, I did not expect stellar performance, but even with only a glClear, it can’t sustain 60Hz, or even 30Hz… I did not bother to measure the actual framerate as the refresh is really perceived as slow…

12 screens should be a nice playground, just have to figure out how to animate something on them… :stuck_out_tongue:

4

Do you have multisampling framebuffers and multisampling enabled? For the best possible performance you should not use any multisampling.

5

No, no multisampling, no depth buffer, no stencil buffer.

Tried to see if WGL_NV_gpu_affinity could help, but the boards does not support this extension.

Trying to setup a WinXP instead of Win7 to see if it helps.

6

It helps ! On XP32, we’re now able to run a simple GL window on all the 12 screens, running a smooth 60Hz white quad moving above a green background…

Now, I got to display more real things.

7

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