Even though Nvidia has told that 400watt psu is enough for gtx 960 do you think that cooler master thunder 450watt is capable of delivering the juice to oc edition as well as the standard edition as I'm low on budget
The power consumption between a stock GPU and a factory OC'd one will not use any significant amount of power. You should be fine with the recommended wattage. It should be able to handle an OC even a little higher than the factory OC.
you need a minimum of 20A and 400w your Psu has both of these covered so i dont see why it couldnt run it. As long as your not running a AMD CPU overclocked you'd be fine.