LED select Red and blue still is COB

[sun yuan]

Such as title A lot of choice Red and blue
made in America CREE COB
Who is better Compared

[DrPhoton]

140lm per watt can be acheived with chip on board.



Cree have shown advancements on upwards of 300lm per watt with around 5k color temperature.



Knowing which ones better depends on so many factors.
You cannot compare LED specs with Lumens as it is a photometry system which is weighted for our vision. Not growing. Theres also how you choose to build, one chip running at full power will be less efficient compared to another at half. This is why LEDs are commonly stacked in a array or chip on board design. If you wanted the very best efficient light, you would grab the best LED chip, run it at its lowest and most efficient power and have a ton of them stacked in a array to provide the amount of light required for growing. Highly expensive, highly impractical.