Hi there your PSU should be fine however i wouldn't risk it as that psu has failed some tests i recommend you get this instead it's better and has a seven year warranty http://www.newegg.com/Product/Product.aspx?Item=N82E16817703028 http://guru3d.com/article/geforce-gtx-680-sli-review/4
Here is Guru3D's power supply recommendation:
GeForce GTX 680 - On your average system the card requires you to have a 550 Watt power supply unit.
GeForce GTX 680 SLI - On your average system the cards require you to have a 750 Watt power supply unit as minimum. If you are going to overclock the GPU or processor, then we do recommend you purchase something with some more stamina.