my system is as follows : 2x corsair solid state drives 128 gig ; 860 , 2.8 i7 processor ; asus p7p55d mobi thermal take frio air cooler 4 x 2 gig corsair dominator 2000mgz modules hunt key 900watt power supply , zalman gs 1000 plus ( black ) case . which is the better card to use , gtx 470 of the ati 5870 and which make would be the best