1 Big Rectangle vs 6 0.1 stud sides? [Optimization]

As the title says, would creating 1 large part be better than creating the sides that make up that shape and leaving it hollow?

Or would it be better to just make 1 big block and not leave it hollow?

You’re getting into some very specific parts about the rendering engine. I imagine one large part, not hollow is better, though performance may vary.