Always the same - that is, always different from each other. 'Finite' has two diphthongs, and 'infinite' has none; also the stress on 'finite' is on the first syllable, and the stress on 'infinite' is similarly on the first, so the two syllables

*fi*- and -

*nite* are as different as they could possibly be! Sometimes I've heard people preserving symmetry by saying 'finite and non-finite' - though 'non-finite' and 'infinite' have different meanings so perhaps they're talking about something else (I'm not a mathematician)

b