The Sonata 3 comes with an Antec EA-500 PSU, which is one of the best PSUs to be paired with a case. The Sonata series is the only series of cases that ship with PSUs where you can actually keep the PSU!
Its not a premium little unit, but it is pretty good and fine for powering a Crosshair V board, assuming you don't try to shove a 270x/280/280x on it you will be fine!