Should work.
1080s are 2x 180W
CPU is 91W
Board an additional 50W
Overall you will prb hit 600-650W
BUT IT DEPENDS ON YOUR CPU OC
However the green CXm is one of the worst branded units available and stressing it.like that is not a good idea
I'd suggest spending on a Rmi850 or an EVGA supernova G2/P2 with 850W to be save.
(750W however can be fine depending on how much you over-clock)