550W should be more than enough for those pieces, but as stated CX and VS aren't the most reliable models of PSU out there.
If you can or haven't bought it, i'd strongly suggest getting a higher quality PSU.
XFX Pro, Seasonic S12, SuperNOVA are great models and will give you absolutely no worries about their quality.
If that's not possible atm, it will work. Just don't push it further with any overclock or multiples HDD/SDD, drivers, etc.