Your compter specs have your power supply as a 460w. That is just not enough power to supply a gtx770 and the rest of your computer enough power. If you want to run a graphics card as powerful as the gtx770 your going to need at least a 550w-600w power supply and for a quality unit your going to have to spend between $50-65 for that.
Out of the two you have chosen, the evga is a 2gb vram while the gigabyte is a 4gb vram model. 4gb is unnecessary unless your going to be running two graphics cards or your going to be gaming on a 1440p or higher monitor. For 1080p gaming the 2gb evga model is about perfect.