I'm confused... and believe me, it doesn't take much.
However, the game does in fact grant faster load times and a noticeably better overall performance by playing directly from the disk as opposed to actually installing the game. Now, while you state the understanding of that, you still note that you may be installing the game anyway.
Now, I'm not clear on the exact "texture" issue you are referring to. Do you mean stutter and lag when being in snowy or rainy areas?
If you are talking about the textures themselves as in they don't render properly or not at all, then that is an engine issue with the LOD or "Z" fighting and I'm afraid it is what it is.