low FPS in no mercy mods

[wwf no mercy mods fan]

i have a problem, I use to play the differents wwf no mercy mods that I've downloaded but from 3 or 4 days ago the game or exactly the FPS are a little bit low, like 27 or 30 and sometimes 50 or 53 but after a few seconds again fall to 27, therefore producing "lag". anybody has a solution for this problem? thank you