Minimum specified on Nivida's website suggests you get something stronger (600W), but it should be fine as long as you're not pushing your system too hard (Overclocking). Also depending on the rest of your build and your CPU, you might want some more power (reliable as well, since dips in power cause performance lost or failure and could damage your components)
P.S. i think the minimum specified is based on the core i7 (correct me if i'm wrong) so it's fine;no worries