This is probably normal for a Luxeon K2 LED driven at those currents. The K2 is not very efficient compared to the "newer" LEDs. Return it and buy something brighter/better online. The X0 is not a bad light, just you could get something better online for the same price.
:welcome:
I think all of the newer X and T series Inovas all use the K2 LED(except the X1 and X5).
chee, time to get a Cree light to see what new LEDs are capable of:naughty:.