I am currently running 2x 400w HPS lamps in my flower room... I am adding 2 more lights soon, I was debating on getting 2 more 600W lights rather than another 2x 400watters. I see pictures online of big fat dense connected buds and while the 400w lights do fine, they do not often produce those monster colas that you would see with a 1000w or a 600w. Not to mention light penetration difference? LEt me know what you think...
400w has about the same total performance as the 1000w but will use less power but not very much less than the 600w. Your buds won't be super dense but it will be good smoke. 600w is the sweet spot for HPS lights. This is what I would get if I was you. 1000w has less average total performance but it will always produce the best crops.
^Sorry, but I can't make sense of this. If a 1000w has less than average performance (which I don't agree with) then how does it also produce the best crops? To the OP, you need to match your light to the space, and you haven't told us how big of a space you have. A 400w should be plenty to give you dense buds, just not dense buds over as large an area as a 600w or 1000w would. A 600w uses 50% more energy than a 400w, simple math. And true that 600w is the "sweet spot" for HPS, with a slightly higher lumens-per-watt ratio than either 400w or 1000w. But a 1000w still puts out much more light than a 600w no matter what.