I mean, I guess you could pull it off with a 530W unit, but it's really pushing it. Nvidia recommends a minimum PSU of 600 W, which is generally on the greater side so Nvidia has themselves covered, but even 3DGuru said the absolute safe minimum is a good quality 550W unit. I would upgrade if you can, especially since power supplies deliver less than 100% over time, even faster if it is running close to maximum draw a lot (for example, in a year, your 530W unit may only be giving you 480W).