Are all 1-2 watt 808nm 9mm laser diodes the same?

Parts you get on Ebay are suspect. It could be they are picking up manufacturing rejects. So every one may look the same but act quite different. At 3V it takes .3A to make 1 W. It takes .66 amps to make 2 watts. It takes 1 amp to make 3 watts etc. P = I*V.