Is it realistic to render a super-high resolution image over an array of 3 by 3 or 5 by 5 (for example) stacked screens? Could I do this by combining several different GPUs, or would the only way be to use a GPU per screen and simply divide the image to be rendered?Ideally I'd like to be able to use fewer GPUs than screens. Even though one GPU is insufficient I'm hoping I won't need n GPUs for n screens.If this is possible I'd also need to know whether this requires using the same make and model of GPU or whether unrelated ones could still share processing.
Can I use several GPUs for a grid multi screen image?
gpu
Yes, it's certainly possible to do this kind of thing.  First of all, you can typically connect 3 or 4 displays to each GPU, and (with an appropriate motherboard) you can have up to 4 GPUs per machine.  That would give you 16 screens.  With multiple machines, you could have even more.Rendering to multiple displays from a single GPU is no big deal.  You can create a single window that stretches across all the displays, render to it, and it should just work.Rendering the same scene on multiple GPUs is a bit trickier.  One way is to create a separate rendering context on each GPU, and essentially repeat all the rendering—re-upload all buffers and textures to each GPU, and re-submit the draw calls to each one every frame.  Another possibility is to use the built-in multi-GPU support in DX12, which allows you to manage several GPUs in one rendering context.