Power Supply Requirements for a single GeForce GTX 960
• NVIDIA specifies a minimum of a 400 Watt or greater system power supply. (Minimum system power requirement based on a PC configured with an Intel Core i7 3.2GHz 130 Watt TDP processor.)
• the power supply must also have a maximum combined +12 Volt continuous current rating of 28 Amps or greater
• the power supply should also have at least one 75-Watt 6-pin PCI Express supplementary power connector. There are some non-reference design cards that require one 150-Watt 8-pin PCI Express supplementary power connector (e.g. EVGA GTX 960 SSC 2 GB [02G-P4-2966-KR], MSI GTX 960 Gaming OC 2 GB [GTX 960 GAMING 2G]).
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.
Cooler Master Thunder 450W (RS-450-ACAB-M3)
• OEM: CWT (i.e. Channel Well Technology)
• maximum combined +12 Volt continuous current rating: 30 Amps <===== Sufficient
• one 150-Watt (6+2)-pin PCI Express supplementary power connector <===== Sufficient
• Modular Output Cables: No
• Official Intel Haswell Compliance: No
• No 80 PLUS Efficiency Certification
• 3 Year Limited Warranty
If your CPU has a TDP that is less than 130 Watts then it should work.
Post your full system specifications and you may get a more accurate answer.