Every light in the display needs to be powered. If the lights don't get enough, they will be dim and the colors will start to fade. This an especially big problem when displaying white as it tends to appear yellow and orange without enough power. Rather than a single large power supply, I have numerous smaller units strategically placed around the yard. These includes power supplies which are specially designed for LEDs and produce a single voltage output. I also have some standard computer power supplies which produce a number of different voltages. The lights run on either 5V or 12V which means a computer power supply can power both while LED power supplies can only do one type.