1st of all ur psu is good enough to run 9600gt and 9800gt.
Now yar why u not believing me about fake cards from xfx. U may ask any forum member over here he'll tell u the same, coz many members bought those fake cards that's why we know.
Now one more thing xfx is not responsible for these cards, xfx releasing these cards with very very low price for consumers who can not afford but here in pakistan retailers like galaxy and others selling those cards at full price with genuine name tag, but those cards are not original 9600/9800gt.
So stay away from them.