(sorry my english is not very)
Helps to get rid of low textures, is the fast camera rotation a bit from side to side or (but not 100%-camera zoom right mouse button). This issue started happening in the 0.62. Before 0.62 I dont have such big problems with not loading textures. In game I have a solid 60FPS. I heard that this often happens on laptops but on the PC too.
My in game settings:
Video Memory: auto or 2048 (no difference)
Texture Detail: high
I checked DAYZ cache, I updated NVidia driver nothing changed.

For example in Arma3 or Arma2 I dont have any problems, all textures always in hi-res.

Here are just a few examples: (before and after fast camera rotation from side to side):

And one more thing
After starting the game, I observe these strange artifacts when loading textures. This happens only at the first start of the game during the day (for example)