Can my Corsair 500W PSU handle a Radeon 7790?

I want to get a discrete GPU as an upgrade from the A8 APU I've been using for the last year. The CPU part has been slightly overclocked to 3.2 Ghz. Can the PSU handle it?

Yeah, your psu will handle it well, you may not hit the 50% sweet spot for pus efficiency but it will be fine.
For referenceI have a i5 2500k @4.5ghz and a GTX570 OC'ed and under load i pull ~400-350W from the wall.