R9 280 with 500W PSU?

Hey, there's a Gigabyte R9 280 on sale at NCIX, and I was wondering if I'd be able to run it with a Corsair CX500M. The CX500M does have two 6+2 PCI-E connectors, but would there be enough overhead? PCP says there's about 100W remaining, so would that be good? It'd be an upgrade from a 270, which I could put into my parents' rig which has a 265, which I could put into my brother's comp which has an A8-5600.

 

Let me know, here's the PCPP link to my current rig WITH the 280. http://pcpartpicker.com/p/3qcst6

Yeah you should be fine

Yeah it'd be completely fine :)