this is probably above most people heres level but.. which is better for efficiency... or better yet, which setups have been able to show the most efficiency per par... samsung strips with an aluminum rail heat sink vs
hlg quantum boards using the same diodes. Which is most efficient.
It's not that simple...
1. The diodes have an efficiency themselves. Like the 301h is more efficient than the 561c
2. The more diodes you put under the same wattage through them (ie 2000 diodes with 600w driven through them will be less efficient than 3000 diodes with 600w) so number of diodes is important when comparing lights.
3. Different spectrums have vastly different efficiencies so you can run all red and have very high efficiency and shit performance in practice because its beneficial to have all spectrum as the plants have different photo receptors.
4. Temperature can affect efficiency so a good heat sink or system for cooling is important. (Fan driven waste efficiency on power for fans)
5 plants use different spectrums more efficiently red being most I believe then blue and green last. But all are important each receptor can only absorb so much. Green while being the lowest also penetrates the canopy much better than red or blue so you are getting an increase to the overall photosynthesis of the plant by using leaves that would not be photosynthesizing as much otherwise.
Then add to this the photo biological and morphology effects and it further complicates things.
Granted intensity trumps all and the more photons the better up until you start to reach the saturation point of those receptors and then spectrum is the only way to increase photosynthesis further.
Now add to that spectrum for different stages of growth.
It's a very complex answer and one that is not definitive yet and likely won't be for some time... even then you have different genetics that will not all prefer the same... so yeah basically your question is splitting hairs when it comes to the higher end lighting of LED
You are starting to see in some cases much more far red added to fixtures which while has a benefit also inflates the ppfd output because they are most efficient at producing photons per watt. I can't say at what point its optimal but I can bet in some cases that's being taken advantage of for advertising purposes.