leds just don't have the power to grow big buds

I have 4 leds called magnum + the light intensity just is not there i was very bummed out i spent 3800 bucks on the lamps . my harvest was small about 1 lb on a 4x 8 table so back to the drawing board so i now have 3 1000 watt HID lamps covering a 5x13 ' space the plants are 10" tall time...