For a single GeForce GTX 560 Ti graphics card system NVIDIA recommends a 500 Watt or greater system power supply with a minimum +12V current rating of 30 Amps and at least two 6-pin PCI Express Supplementary Power Connectors.
For a two GeForce GTX 560 Ti graphics card 2-way SLI system NVIDIA recommends a 700 Watt or greater system power supply with a minimum +12V current rating of 45 Amps and at least four 6-pin PCI Express Supplementary Power Connectors.
Since it's the power supply's +12V current rating that primarily determines whether it is suitable for your system, both the XFX P1-650X-CAH9 650W and the CORSAIR Enthusiast Series TX750 V2 750W, that you have linked to, are both capable of handling a two GeForce GTX 560 Ti graphics...