Textures appear grainy from a distance during movement

[The chaser]

I have made a handful of materials and I'm using them as wall, floor and ceiling plains. I have a simple diffuse and normal map for the materials and I'm more than happy with just those two files, as it stands.

Problem is, when I'm looking at a primitive from a distance while moving the mouse, the materials seem to grain but when up close and personal with them they appear just fine. I have tried de-noising them them with CrazyBump since I thought that was the issue but it seems it wasn't or it just didn't work properly or whatever the case may be.

If anyone needs a visual example, I will upload a clip if necessary. I hope I was descriptive enough. I "could" live with the results I currently have but would be much more content if this could be fixed since it's rather bothersome.

If you say it gets "Grainy" from a distance, MipMaps should be the problem. Try exporting the .dds again without mipmaps