So how does it come that with the exactly same scene everything went fine with older VRay versions ? Maybe VRay has something to do with this problem nevertheless …
I tried your trick: no viewport in my scene is saved in “Realistic” mode: all viewports have been saved in “Wireframe” mode but the problem remains the same: 4 minutes to load a scene which loads in about 15s with previous VRay …
Too bad. I am going to wait for 3dsmax 2013 and cross the fingers 
Thank you for your help anyway,
Best regards,
AltoR