The “dual-chip” is indeed helpful to the flexible design of series or parallel, especially in the luminaire like an A60 bulb, and driving at low current with multiple-chip is generally considered as the natural way to improve the efficacy. It is correct in the past few years but with the quick development of the semiconductor LED die, it is no longer the essential method. For specific wavelengths or radiant powers, only talking about efficacy, sometimes applying the “single-chip” with larger size could achieve the same or even better result, and the cost performance is equal or even better.