GeForce GTX 460

Elias says:

I would like to ask a question that bothers me for a long time. I am trying to find an answer, an explanation about a problem I have in my understanding of power consumption of PSUs. There are sites that offer methods of power consumption calculation of a desktop system. This calculator shows that referring to the selection of a Graphic Card, the manufacturer is not important. That leads me to the conclusion that all the same models e.g. GeForce GTX 460, will have the same power consumption regardless of their manufacturer. This conclusion comes also from this site where it is shown that GeForce GTX460 has power consumption of 150 Watts regardless of the manufacturer. What bothers-confuses me is that at the EVGA Products Site it is shown that EVGA GeForce GTX460 needs a minimum of 450 Watts power supply. There is a difference of 300 Watts. Perhaps I miss something in this. Please help me to understand what is the meaning of these different power consumption indications. Thank you in advance for any explanation-answer.