If it's Sony's NB, and Sony's weird power-saving mode designed to extend the life of VAIO notebooks, it's related to the optical drive anyway.
DVD-SM is a super multifunctional DVD burner, which seems to be used only on NB. Anyway, I saw it on NB.
DVD-DRAL is a combination of DVD-RW and DVD+RW specifications, initiated by Sony. Although there is no problem with the choice of DVD, it is more expensive because it has paid two patents.
COMBO can read DVD discs but can only engrave CD discs, which is quite affordable. COMBO is recommended.
(DVD-SM, I'm not sure yet. Please give me some advice. )