.X or .B3D?

Simple one this:
I have an embarrasing number of entities in a single scene each in .X format. Will it help fps (and/or loading time) if I convert them all to .B3D? Or is the difference not worth the work?

It won't make a difference.

Thanks, you probably just saved me a couple of days work. But can you say why?

Internally (once loaded) they are the same. B3D might help a tad on the loading time, but it probably won't be noticeable.

If you can squash any of them into a single surface that will help more.

Er... as in 'blend all the child entities into a single entity'?

Nope. As in blend all the surfaces in all entities into one (or as few as you can manage).