So is this possible? Can i run these two cards in crossfire together? Or would i need another 390 to run crossfire properly? Im newer to the Graphics world so i apologize if thats a dumb question.
No you cannot crossfire them at all unfortunately as they are not in the same family of physical chip that is used on them.
We're all hoping for DirectX 12 to allow for use of varying cards to be able to be used together but that's some ways off currently. So just stick with either just using the one 390 or get your self a second one to crossfire with it.
Further to this. When crossfiring two or more cards together the better card will always be clocked down to the speed of the slowest card. So even if you could crossfire your 390 with your 270x you would essentially have the same power as two 270Xs running in crossfire with each other.
So yeah in short you practically cannot crossfire those two cards together. Hope that explains...
They need to be in the same family so the 270 is Pitcairn which includes R9 270X, R9 270, HD 7870 and HD 7850 while the R9 380 is Hawaii\Tahiti which includes R9 390X, R9 390, R9 290X, R9 290 and HD 7970.
No you cannot crossfire them at all unfortunately as they are not in the same family of physical chip that is used on them.
We're all hoping for DirectX 12 to allow for use of varying cards to be able to be used together but that's some ways off currently. So just stick with either just using the one 390 or get your self a second one to crossfire with it.
Further to this. When crossfiring two or more cards together the better card will always be clocked down to the speed of the slowest card. So even if you could crossfire your 390 with your 270x you would essentially have the same power as two 270Xs running in crossfire with each other.
So yeah in short you practically cannot crossfire those two cards together. Hope that explains things for you
Also if you do decide to get a second 390 you need to make sure you have good quality and powerful enough PSU to run your system. As 390s are Hot power hungry cards