It's not the greatest PSU , but it will handle a single 280x , but no overclocking.
A new power supply made by SEASONIC , XFX , Antec , Corsair not CX Series in the future would be the way to go.
That's the card I plan to get nice, I would try to get a different power supply after a little bit but you can use the one you have now. What is your computer now?
Power Supply:XFX 650W 80+ Bronze Certified ATX Power Supply ($66.99 @ NCIX US) Total: $66.99 (Prices include shipping, taxes, and discounts when available.) (Generated by PCPartPicker 2013-11-24 13:46 EST-0500)
That's the card I plan to get nice, I would try to get a different power supply after a little bit but you can use the one you have now. What is your computer now?
my current pc specs: A10 5800K, Radeon 7870 ghz edition, 8GB Crucial 1333mhz RAM, 1TB hard drive