Textures loading slower....FPS dropped some well...Even GPU has no overload

I limited maximum texture load to 200, and later 400... Still,the textures load to the limit SLOWER than it used to, thus making the game lose FPS.
Gamebooster ON + Defragged folder but nothing changed. Traffic less than I used to,still no enough. When I used to get 20-25fps,now I get 10-15fps or less even settings lowered.

What can it be?