What is the difference between 3D and IMAX 3D?

Ok, so I'm going to see Harry Potter and the Deathly Hallows Part 2 at
IMAX next week, but I was wondering what the difference was between
going to a normal cinema and seeing the film in 3D and IMAX 3D. I know
that IMAX has a bigger screen and better sound system and everything,
but I mean in terms of 3D? ;) Thanks.