performance and collision with visible objects

[mogli]

hi!

hope my question is not to silly.

i want to optimize my app and ask myself if it's a strong difference if i set all the visible objects to collisionmode check_others and collisionmode check_none.
the actual room with the user inside must certainly set to check_others.
but the neighbour rooms have only to be visible.
so i could change the collisionmode with every "room-change".

hope it's to understand what i mean.