Just change the power supply to make me (and you) happy. We've had a lot of problems reported with the CX psu. They are only 3rd tier on http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html.
You only need 500W . But from a good quality psu eg Seasonic 520, XFX 550 or Antec HCG 520M
Otherwise - great build!!