Anybody have any idea which will perform better? Historically two cards one model under will outperform the top of the line model. It appears as if 2 r9 280x's will be about the same price as one r9 290x. thougths?
Two R9 280x' will be better than a R9 290x. Two mid-range cards are most of the time just as good as a high-end card, however the R9 280x is a high-end card. I can't say for sure, but if you google some R9 280x crossfire frame rates (guessing that the R9 290x is barely better than a GTX 780) and see if it's better than the GTX 780. What you'll get from that is probably what i just told you.
The crossfire should perform better (better as "more fps") assuming that the 290x performs at the Titan level, but I think we have to wait for the actual launch of the card to have valid benchmarks to base our opinions.
Two R9 280x' will be better than a R9 290x. Two mid-range cards are most of the time just as good as a high-end card, however the R9 280x is a high-end card. I can't say for sure, but if you google some R9 280x crossfire frame rates (guessing that the R9 290x is barely better than a GTX 780) and see if it's better than the GTX 780. What you'll get from that is probably what i just told you.