Sup jay, are you using better smoke and ballistics mod? http://www.nexusmods.com/newvegas/mods/38550/?
I don't know if you are already using this, but if you are deactivate it see what happens.
If not install this see if it works. Having two versions of the same mod may lower FPS <3
I don't know if i read your topic properly, i may be suggesting something you already tried based on your topic name