Bosson, you can speed growth, but you can't speed maturity. For example, If we did side by side grows, one with a 1000w HPS and another with a couple of CFLs, they would both take relatively the same amount of time to harvest, the only difference would be that the plant grown with the HPS would be much larger, and have a lot more bud weight. So while it is possible to increase yields in a given length of time with more powerfull lights, it won't change the fact that you'll still need 11 or 12 weeks from seed to harvest, at the very least.
you gotta be F!'in kiddin me. i want it to get bigger quicker than the sun. how do i do that?
You can harvest a plant QUICKER under artificial lighting because you have control over the photoperiod, which means you have control of when the plant will flower, but they certainly won't be BIGGER. Size depends on few factors not in any particular order of importance (assuming that the environment and nutritional requirements of the plant are met): The first limiting factor is the plant being able to form a large root structure. The second limiting factor is time, the longer you veg a plant (given that it has ample room for root growth), the larger it will be. The third limiting factor is light, a 400w HPS may seem bright, and it is, however, it is subject to the inverse square law that states that for every doubling of distance from the light, luminosity is 1/4 of what it was. So indoors, you are limited on how large you can have a plant grow. If you have a plant that's 6 feet tall indoors, the amount of light the plant receives from top to bottom is progressively weaker due to the inverse square law. Outdoors this isn't a problem because, while the inverse square law also applies to the sun, you have to keep in mind that we are 146 million kilometers from the light source, so you'd have to travel another 146 million kms away from the sun to reduce the suns luminosity to a 1/4! So the difference in the sun's power from the top of a 6 foot plant to the bottom is almost immeasurable it's so tiny. The reason you see the huge trees that some people grow outside is due to the fact that the root mass can spread as deep and wide as it wants, you have a light source (the sun) that provides even lighting power from the top to the bottom of the plant, and because people typically plant in the late spring, or early summer, providing a soild 2 to 3 months of veg time.
In summary, you can harvest quicker inside, but not bigger. That's why there are indoor growing techniques like SOG (Sea of Green), where instead of having one or two large plants under a 400w HPS which makes inefficient use of the light (due to the inverse square law I mentioned in the previous paragraph), you have 9 or 10 smaller plants that make efficient use of the available light. The advantage of this is you only have to veg for a short time allowing you to get quicker harvests, and while you may only get a small amount of bud from each plant, there is more total bud because of the larger number of plants and more efficient use of light.