NAD-dependent (R,R)-butanediol dehydrogenase which catalyzes oxidation of (R,R)-butane-2,3-diol to (3R)-acetoin, of meso-butanediol to (3S)-acetoin, and reduction of acetoin. Allows the use of 2,3-butanediol as an aerobic carbon source. (R,R)-butane-2,3-diol + NAD(+) = (R)-acetoin + H(+) + NADH Binds 2 Zn(2+) ions per subunit. Homodimer. Present with 8730 molecules/cell in log phase SD medium. Belongs to the zinc-containing alcohol dehydrogenase family.