Not really sure here. Saw gtx770 super clock requires the 12V rail with 42amps. I would use the Antec HCG 750W which states:
+3.3V@25A, +5V@25A, +12V1@40A, +12V2@40A, +12V3@40A, +12V4@40A, -12V@0.5A, +5VSB@3.0A
For a system using a single GeForce GTX 770 graphics card NVIDIA specifies a minimum of a 600 Watt or greater system power supply that has a maximum combined +12 Volt continuous current rating of 42 Amps or greater and that has at least one 6-pin and one 8-pin PCI Express supplementary power connectors.
Total Power Supply Wattage is NOT the crucial factor in power supply selection!!!Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) is the most critical factor.
Overclocking of the CPU and/or GPU(s) may require an additional increase to the maximum combined +12 Volt continuous current ratings, recommended above, to meet the increase in power required for the overclock. The additional amount required will depend on the magnitude of the overclock being attempted.
The Antec High Current Gamer Series 750W (HCG-750) power supply unit, with its maximum combined +12 Volt continuous current rating of 62.5 Amps and with four (6+2)-pin PCI Express supplementary power connectors, is more than sufficient to power your system configuration with a single GeForce GTX 770 graphics card.