Vray displacement


I’m trying to understand better the “displacement” topic. For example, I find very interesting the fact that instead of modeling a whole metal corrugated roof I can just use one of the many textures found on the internet and use “displacement” to give them the 3d effect.

The problem:
every time I am applying to a polysurface that texture, most of the time I’m having problems rendering with Vray GPU (not rendering, crashing, etc)

Are there any constraints/rules I should know to make it work properly?
i.e. I was reading that I should subdivide the polysurface to make the process easier…