This page further details the advantages of the XB-D versus a typical backlighting LED in an 800 lumen omnidirectional A19 lamp. As can be seen in the graphic on the left, 12 XB-Ds can be laid out in many different configurations within the 35 mm diameter space referenced in the previous slide, with plenty of room for an omnidirectional optic as well. In contrast, if typical backlighting LEDs are used at the widest part of the bulb, measuring 60 mm in diameter, there will only be enough room for the 58 LEDs required to achieve 800 lumens. As a result of the position of the LEDs and the lack of space, an omnidirectional solution  is not possible using backlighting LEDs. While it’s true that both solutions have comparable power consumption and efficacy, the advantages to a solution that uses 80% less LEDs and that has many more design options are quite obvious.