vray RT slow changes...

Hi all, from 3.0 version of Vray we found ( 4 pc and 4 different licence) that Vray RT doesn’t update quick!
In fact when i change a material, or other stuff, it take 8/10 seconds ( sometimes more) to update the render even if i have a render-region.
I use RT not for final render but only to setup my my scene…so i cannot use it if it doesn’t update quick…(Vray 2.4 was quicker and ok).
Is it a bug?

Would it be possible to check if you got the same behavior with any scene or it persists only on particular one.

The same for all scenes, with different pc, difference licences and different people. :(. it started with new vray 3.0…

Is it possible then to send us one of those scenes for investigation?