Yes you will be o.k. 660 Ti - On your average system the card requires you to have a 450~500 Watt power supply unit. Measured power consumption
System in IDLE = 132 W
System Wattage with GPU in FULL Stress = 258 W
Difference (GPU load) = 126 W
Add average IDLE wattage ~10 W
Subjective obtained GPU power consumption = ~ 136 Watts