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
if i choose to run 2 cards which i prob will do , some say that asus board will performs better in cross fire than in sli , is it better to get 1 huge card or 2 smaller cards , ei : 2x 5870 or 1 x 5970
If your board supports SLI and CF then they will both work perfectly fine on your board , doesn't matter whar make your board is.
Generally its better to get the single fastest card you can afford as it takes up less space in your case ( 2 slots, instead of 4) and leaves you with the option to get another card as an upgrade in the future.
With your example the 2 x HD5870's will perform about 20% better than a single HD5970 but will also use more power and so will generate more heat.