Best 2 yields i pulled recently from 2 grows
First one had 16 AG13 Hazes under 4 x GAVITA 600W/400V PRO'S and yielded 5,2K, so about 1,96gr/w and at a 1,5x1,5x2,3m tent growing 4 Bandaid7 plants under a 600W/400V Lumatek, these 4 B7's yielded 1260gr, making 1,91gr/W.
Basic setup, sufficient air supply, outdoor environment was ideal making all other crucial variables balanced throughout both runs.
Normal runs mostly between 0.9 to 1.6gr/W
Never seen anyone yielding over 3gr/W IME.
Talk about setting the bar, i rather have a bit less but superb gear then the overboosted gear on whatever boosters including adding CO2. Then again, i'm pretty old skool so that's prolly the reason i aint scoring such yields.