Hello, i want to get max out of my machine, do I buy 2 HD 5770 cards or one HD 5780? If I look at the specs I see that the 5780 is "double" the 5770. But if I would place 2 5770's would they work together to become equal to a 5780, but with double the display outputs? Or are the double display outputs my only advantage and do they not work together when performing GPU based rendering? Any other pros and cons are very welcome. Thanks.