On the specifications page for each of our NVIDIA professional graphics boards, we state the maximum power consumption. Subtract the total power requirements of your current configuration from the total Wattage output rating of your power supply. As long as the remainder is greater than the maximum power consumption of your NVIDIA professional graphics board by PNY, you will be fine.
If needed, you may use a free power supply calculator (see the link below for an example) to determine whether your power supply will meet the overall power requirements of your configuration:
http://outervision.com/power-supply-calculator
If you need further help, please call PNY Pro Graphics Support at 800-230-0130.