I have the 770 and I can run it with the minimum 600w power supply while overclocking my CPU. I heard that 550w is stretching it. But from what I know, if you don't overclock or anything, you might be able to pull off a 500w power supply. However I do not advice it. I'm already pushing it with a 600w, so 500w is a little small. I would try it though, there is no harm in that, if the PC shuts off on boot, it probably can't handle it, either way I suggest upgrading to either 600w+ just to be safe and a little more future proof. The answer is yes, you can run the card with 500w, but I'm advising otherwise. Hope this helps!