I didn't use any static or rigid object. I just call "physX_load" function.
When the level opened, major fps decrease for the first minute. After about a minute, fps came back to normal value.

There are a lot of complex shader models in my level.
I closed shaders effects of all models and I tested "physX_load" function again. This time did not have any fps drop.

Why do physX_load function decrease FPS for the first minute?

PS: my graphic card is 9800 gtx

thanks in advance