ok im thinking of buying a evga gtx 660 video card.....my power supply is a 600 watt with two 12 volt rails the 12v1 rail is rated at 23amps the 12v2 rail is rated at 20amps......my question is the specs on the video card state that the say I need 450 watts and 24 amps on the 12 volt rail.......do I need to upgrade my power supply....or should I be ok?