Not so sure if it isn't significant. Having in mind the pictures I wouldn't be surprise if the 90 CRI yielded 30% more or so. That would be enough to justify the upgrade, the new COBs would be paid off in a single grow.
Before any conclusion/change I will wait for the final weights.
I have no validity to confirm this and I am talking specifically about Citizen 1818s, but I will be using 4k 80cri for veg, in hopes of getting less stretch and aiming for maximum efficiency. However, I will be swapping to 3k 90cri when I flip them. I don't think they're "bad" so much as different i.t.o pros and cons. I think there's more to this topic than just assumptions and anecdotal evidence.
Maybe Mr
@CobKits could weigh in, with an expert's opinion, but I based my decision on the spectral output of each cob.
As you can see here, the 4k 80cri cob has a relatively even response in terms of reds and blues. I am hoping that this shift will simulate summer morning light. The 20% cutoff on this is 690nm, with 660nm ("photo red") having an intensity of only 45%. Blues peak at 91% over 450nm. If you look at the area under the curve, the 4k 80cri has the "most" output of the bunch, which equates to it having the best efficiency (ignoring ppfd etc)
Compared to the 3k 90cri, which I am hoping will give me more stretch and vigorous growth. This cob has significantly less blue light and has 20% intensity at almost 725nm - giving us a little far red and a whole lot more 660nm (80%) whereas blues also peak at 450nm, but with only 60%. This curve has considerably less area under the curve than the 4k90cri and I assume then also the 4k80cri, meaning it's less efficient
In summation, again specifically considering the 1818s,
4k80cri: (130lm/W at 1200mA according to what I've got written down)
20% max: 690nm
660nm: 45%:
450nm: 91%
660:450 2:1
3k90cri: (162lm/W at 1200mA)
20% max: 725nm
660nm: 80%
450nm: 60%.
660:450 1.33:1
Again, I think they are different tools and a balance needs to be struck to get the best out of plants. Not to mention, so many strains respond so differently that one man's recipe to success may not be the recipe to your own success.