For a system using a single GeForce GTX 660 (non-Ti) graphics card NVIDIA specifies a minimum of a 450 Watt or greater system power supply that has a maximum combined +12 Volt continuous current rating of 24 Amps or greater and that has at least one 6-pin PCI Express supplementary power connector.
An exception is the MSI GeForce GTX 660 HAWK 2 GB. It requires two 6-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.
Corsair CX Series CX430 (SKU# 75-001666 / CP-9020046)
• OEM: CWT (Channel Well Technology)
• maximum combined +12 Volt continuous current rating of 32 Amps
• one (6+2)-pin PCI Express supplementary power connectors
• Modular Output Cables: No
• Official Intel Haswell Compliance: No
• 80 PLUS BRONZE Efficiency Certification
• 3 Year Limited Warranty
Corsair CX Series CX500 (SKU# 75-001667 / CP-9020047)
• OEM: CWT (Channel Well Technology)
• maximum combined +12 Volt continuous current rating of 38 Amps
• two (6+2)-pin PCI Express supplementary power connectors
• Modular Output Cables: No
• Official Intel Haswell Compliance: No
• 80 PLUS BRONZE Efficiency Certification
• 3 Year Limited Warranty
Stay away from Deer power supplies unless you like to see an exploding power supply.