I would NOT Get a CX750 for that build, Owned 2, both of them are dead, Damaged some components along the way, Cruddy units. Heard a story of a guy that built 5 computers with the CX Units and 4 of them died.
Bit the Bullet and went for a supernova G2 and have never regretted it, Computer runs smoother than it ever did while under the CX units.
I'd save up and least get a Supernova G2, RM 750/AX760 or a seasonic unit, May hurt the wallet but a quality PSU will be worth it, Specially with a Overclocked i7.