why sometimes i can only have one camera window and others will be empty????

hi.i’m doin my proj with two monitors connected to two graphics card on a system:two monitors beside each other.i need 2 camera windows in my workspace.i dont know why but sometimes one of those windows is empty (when i open the saved project) and it wont display anything even if i change the frame.and every new camera windows will be empty.

I am guessing cause all the processing is done on the primary graphics card.

If your graphics card has 2 outputs use that instead.

maybe you are right about 2 graphics!!!but if that is the case why it happens sometimes???not always???

Well that blows that theory up.

Is one of the cards not supported in the min requirements?

no i dont thonk so.one is 5400 and another 6500 ati.i dont really know the exact information about the graphic cards

•NVIDIA® Video card fully supporting OpenGL with 256 MB of RAM (recommended 512MB for 3D model support)

<— that is what is required.

i found how to overcome it.when i saved my file i needed to trim my workspace in one monitor or change my workspace to default.then when i opened my TB and change my workspace to 2 monitors and it would be fine.strange isnt it???i think there’s a problem between two graphics.
thank you