I wanted to know some general info about Crossfire. I'm going to use the R9 285 in my questions, and I know there isn't much info on them but you guys can use other cards in your answers. So here are my questions.
1) AMD announced that the 285 will come in 2GB & 4GB configurations. Can I use a 4GB card with a 2GB card. For example if I wanted to use the 2GB card for the monitor & the 4GB card for everything else would that work?
2) If I were to use a 4GB & 2GB cards, would the 4GB card be downclocked and would the memory go down to match the 2GB card?
Yep,it will use only 2 gb. I remember that people used to run a 7950 and a 7970 in crossfire and the 7970 downclocked to match the 7950. I may be wrong though,someone correct me if I'm wrong.
Cloud is right, the two cards will be downclocked and downgraded to match whichever card is the weakest or has the least memory if they are running in a crossfire configuration.
Yeah, unless they changed something, it should work fine... though the 4gb model would be limited to the performance of the 2gb model as the other's have said. So basically, it kind of negates the point really. The single 4gb model will likely perform better on it's own than the two in crossfire, and without the extra crossfire quirks and issues.