i was going by this:http://www.realhardtechx.com/index_archivos/Page447.htm
and looking closer one model is seasonic and the other is channel well. sorry i got mixed up for a minute.
though it is highly unlikely the card(s) will hit its TDP; gaming power consumption is ~200 watts on the card (of course depending on the model)
to be honest the only thing i think is less likely then the card hitting 250 watts is the OP actually getting a second one unless they are saving funds towards that now along with another monitor; because gaming @1080 with 7970 Xfire is the definition of overkill