no matter how u look at it every card can be Overclocked with a Non reference cooler the GTX670 is a 760 a R9 280 Overclocked outperforms a 760
so i would go with AMD cards regardless 1080P NEEDS THAT 3GB OF RAM so if u can afford going with a R9 280X go with the 280X if u cant go with the R9 280
i would recommend either sapphire or MSI cards also when u get the card just Overclock it and u will outperform any the 760/670