I made a scaled set of the hi-res textures for V4 and M4 because 4000 x 4000 textures are justoverkill for the image sizes I normally use. If something is in close up I will reload the full size texture.  4000 x 4000 = 16 mb x 3 (color depth) 3000 x 3000 is 9 mb x 3 so about half memory requirement.