black plague, extreme particles lag *please help*

[BlueFury]

So Yeh I am playing black plague for a while now
The problem is when I come near gas/smoke (particles I think)
It starts to lag a lot

*spoiler warning*
When I tried to lock up the professor who needed a saw for his hand in the
Computer room, it was lagging all over the time in that room because of the smoke, also the fight with the worm was almost impossible


Ya know its the kind of lag where you move a second after you push the key


I have an Intel 965 chipset on a 2gb RAM laptop, I can play with more than 40fps and everything maxed out. Not without lag when I'm near gas/smoke