I'd have to see a side by side of one of those qb96 and a 400 watt hid. From the par charts I've seen it would take 4 of those to get the same intensity par coverage as a 400w hps. More to it then just par output?
I've done a grow with a viparspectra par 700 and now I'm using these QB 96's but the jury is still out until my current grow shows her hand. But I'll know in about 4 weeks, so I'll be interested to go through this thread, pass on what I've found about these boards.
The only way it would be true that the intensity of 4 of these QB96's would equal the intensity of a 400W HPS would be if each of the boards was driven at less than half power. Even in that case you'd obviously get better coverage with these, either 4 in a line in a 2 x 4 space or 4 in a square in a 3 x 3. Then of course there's the versatility of adjusting the power, height and angle separately. Also running them at 90W would run pretty cool.
Currently I'm running 2 QB96's in a 2 x 4 foot space each with it's own 185W 54A driver. I have them drawing 3.8A at 55.4V and with a 30W pedestal fan pointing at them the temps are 48C and 58C which is pretty good, without the fan they'd hit 85C so it doesn't take a lot to cool them down.
However these two lights putting out 420W of power are drawing 470W at the wall. Now my Viparspectra 700PAR was in a 2 x 3 space and did a pretty good job, it's 325W at the wall on full power. However I would only use it at about 250W by running Red100%White100% and Blue at 20% for flowering. Now if I put two of these drawing 500W at the wall in a 2 x 4 foot space, would this be better than these two Elites drawing basically the same wattage at the wall?
I don't know the answer to that.
Migrow just did a ppfd test