sora :
I doubt there would be much of a difference. What are your other specs? If you really wanted to you could return it and get the 650W PSU.
CPU:Intel 4th gen i5 -4670k
CPU cooler:Cooler Master Hyper 212 EVO
GPU:EVGA NVIDIA GTX 760 02G-P4-3765-KR
RAM:Crucial Ballistisx Sport 8GB(2X4GB)
OS:Microsoft Windows 8.1
MoBo:MSI z87-g45 Gaming LGA 1150
SSD:Samsung 840 EVO 250GB SATA III
HDD:Seagate Barracuda 1TB 7200RPM 64MB Cache SATA 6.0GB/s
Optical Drive:Asus DVD-Writer Black SATA