Yes it will bttlneck in crssfire
but it has hyper threadin and is more powerfull than amd 6300
So it can handle single cards like 7790 or even 7850 & 7870
bttlenckin in crssfire
And doin a crssfire is nt good amd themselves admitted that CF causes problem like micro shutterin and they are tryin to fix it
I wud reccomend u to sell ur 7790 and buy a 7870 ghz
This is the best u can do