I might be wrong, but I don't think it matters if the room was built with the 32 or 64 bit client.
In the end, the world files are simple text files with information for each object (size, position, rotation, material, color, etc.).
In my experience, the position glitch, where an avi seems to be in another position than it really is, is more common when you have big height differences in your room (a tall building or structure).
Lag is most common due to use of reflecting surfaces or smoke / water / light effects.
What do you mean by "the noise"?