[Brian Yip]

x-refs = external references = import a max file into your scene without copying the objects = save disk space.

If you need to transfer a file with x-ref models to another computer, you also have to transfer the file of the x-ref-ed object to another computer.

I believe x-refs save your time in loading the file and your disk space. But it will not save your rendering time.

hint: if you use x-refs, you need to label all your parts and all your files so you can definitely recognize them just by looking at them.