OSL on GPU

[StefanW]

@SteffenD

BUT: If I switch to CPU with OSL they all of a sudden render instantly with only ~150MB per texture.
OSL seems to use the mipmaps and therefore uses a much smaller resolution I guess?

Yes, OSL is using OpenImageIO’s tiled mip map cache for all textures that are referenced as files (as opposed to being packed into a blend file).