no.
amd doesn't allow crossfiring two different generations of gfx cards. you can either cfx with another 6870 (not recommended at all) or sell your current card and get the asus r9 270x and use it as a single card
no.
amd doesn't allow crossfiring two different generations of gfx cards. you can either cfx with another 6870 (not recommended at all) or sell your current card and get the asus r9 270x and use it as a single card