FPS too few

[1823250971@qq.co]

as time goes on，FPS will drop to 15 or so。
computer specs：AMD X4 760K、GTX660、8G RAM

I try to down some game profiles，but it is no use

[Wolf]

Try with / without hd textures (switch in launcher)

[1823250971@qq.co]

Try with / without hd textures (switch in launcher)

i try，but when i play 20min ，FPS still decreases