I do know that my motherboard (asus M5A97R2.0) supports crossfire, and currently the HD 7700 is what I have. I am thinking of getting a sapphire 7870 to be my primary, and link the 2 through crossfire. Is this possible? I checked the crossfire faq, but didn't see the sapphire or the 7700 (only 7770) on the chart.
Ok, so after another hour of research, if found on AMD's tech support site that you CAN crossfire two different cards with different speeds, BUT doing so will cause the higher end card to run at the speed of the lower card.
What I still need to know at this point is if there are any issues with compatibility between the sapphire and the HD 7700, and if not (or unknown), then is the drop in performance with the sapphire so significant that it makes Xfiring the two completely pointless, OR will it still boost the overall performance?
it won't be possible to crossfire between the hd7770 and hd7870, in order for crossfire to work, the cards have to be from the same series
ie. hd77xx, 78xx (only first 2 digits are important here)
in other words, you can crossfire the hd7870 only with a hd 7870 or a hd7850. The hd 7770 is from a different series and you can only crossfire it with another hd7770 or a hd7750.
You best bet would be to get another hd7770 to crossfire or sell your hd7770 and get a hd7870/7950