I agree with cravin.
Plus, another tip.
1080p gaming can barely saturate 2gb on max, 4gb is for multimonitor.
If you ask me, I'd get the 670 which proved to be the best value on the nvidia side this generation, but dont worry about memory, 2gb is enough for 1080p: you have to priorize the cooling solution, because overclocking will be your friend.
And if it comes to overclockin, I honestly prefer the amd side, although both are quite good at it. Just an opinion c:
Hope you enjoy your card of choice