New PNY 780 enthusiast edition, questions about power

I just got a 780 not realizing that the minimum recommended PSU is 600w, I currently have 550w. I ran a wattage calculator and threw in some overclocking on both the GPU and CPU and was under the 550 mark. My question is should I trust the wattage calculation and go ahead with using a 550w PSU with the 780 or just heed Nvidias advice and pick up a bigger PSU?



I would rather not spend 50-70 on a new PSU, but then again don't want to risk blowing the 780 or anything else in my PC.



Thanks for your time.

New PNY 780 enthusiast edition, questions about power