I'm waiting for the Pro Elite QB which will be out in a few weeks depending on how much they boosted the red, then I can have two rooms going. Otherwise, to say the viper doesn't have 'power' really doesn't make any sense. Power is a delivery of Joules per second, or Watts. So it has whatever it has, in this case it's about 270W. What you probably mean is that for the given amount of Watts it is using it is producing less photons than a more efficient design. And this is true, but as I am only in a small space with a canopy of 55cm x 70cm and the light is 15" from the canopy then there's certainly enough light to max out what the plant is capable of without additional CO2. If I had 6 of these vipers in a large grow room then that would be a fuck up for sure. And I think I'm getting more useful light from the 270W I'm actually using than say a 250W HPS. I'm only wanting to grow enough for my personal use, I'm not trying to do this for a living.
However in a few weeks I'll see what the result is. This is not known as a big yielder, but it is a high quality smoke. However it was probably not a good auto to top as it's very branchy, but it's my first auto as well as first LED. Hopefully the idea is to gradually keep improving and learning. When I was first growing 25 years ago in hydro, over two years I got my strain up from 6oz to 17oz per plant, but that was just cloning a single strain which has the advantage that you get to know exactly what to do. I'm going to be only doing autos now and I want to try different strains so I won't have this luxury, but I am more of a hobby/personal use grower, so things that are important to a large grower are not important to me. I mean if I've wasted $50 on electricity over a grow, that is not something I give a shit about.