Desert missions makes my pc lag

My GPU just blew up, so i had to use an older card until i get a new one.

i get 100-120 fps in most missions, but the dust clouds and what not in desert missions is tough and gives me only around 20-30 fps.

Is there any way to reduce all that dust or makes it “lighter”

Ive played with the particle thingy, but that didnt help much