One could probably optimize things further with CAT, but in the broad perspective and current practice, DNA will win because it gives you a measure (imperfect too) of every other heritable trait for which a predictor exists.
Looking up prices for a professional psychologist to administer an IQ test in Denmark, typical price is 3000-4000 DKK, i.e. 500 to 660 USD. Even commercial DtC sellers for microarrays go for 99 USD, likely to drop more.