If you have a i5 or higher get a GTX 1070. I have an i7-6700k with 16gb of ram and a GTX 1070. The card is a beast and my setup runs GTAV Ultra with max everything else at 110fps. If you got the money get a 1080 if you can b/c
Of the GDDR5X it has a much higher bandwidth transfer and you should get even better frames. You can go AMD but personally I wouldn't.