Splitting a huge sprite and memory management?

I have a relatively large set of large textures, all 8192x8192. Unity allows importing them as such, but it makes little sense to hold such large textures for mobile environments. How does Unity process a split texture internally and in regards to spending GPU memory?

To be a bit more specific, If I use “Sprite Mode: Multiple” to divide it into sections of say… 512x512 textures and render them at different points manually, does Unity actually separate them into different textures on the GPU or is it just using UV to reference the behemoth? i.e. Do I have to splice it manually in my Graphics editor of choice and import the fragments separately?

The texture is kept intact when using Sprite Mode: Multiple. The individual sprites are drawn from the large texture using texture coordinates.

I’m not completely up to date on the latest graphics hardware, but 8192x8192 seems very large, and may limit the hardware you’re able to run on. I certainly doubt it would work well on mobile devices, if at all. I would suggest smaller texture.