Originally Posted by Mipmap

You have different resolution sizes for a single texture. Up close you have the highest and far away the lowest.



With mipmaps ON, the game automatically generates a number of textures between those stages, so that the transition is smooth. With mipmaps OFF the textures will "pop-in" as you move closer, since there's no interpolation.



Obviously this saves a lot of texture memory, and probably there's something buggy in the game code that makes the creation of mipmaps lag everything.