All major textures in the game were increased to 400%+ of their original pixels, sharpened, and had some detail added. Then new normal maps were generated to take advantage of the greater detail, which results in a significant improvement over the original graphics. This enjoys 0% compression files, which helps offset the fact that larger files requires more system resources.
These are taken from my FNV HiRes mod, for those that do not want to download the full mod. This only installs the HiRes Armor and Weapons. Please note the pic for this is from RegRes, so you will actually get a better result in game. The Pic is Original game on the top and RegRes on the bottom.