Re: GPU thought?!
You CAN put an NVIDIA and an AMD based card in the same system, but they can't both operate at the same time - you'd need to turn the PC off and change the card that the display connector is plugged into (plugging two cards into non-matched slots on a mobo, it will ignore whichever one has no video cable plugged into it).
a high-end AMD card will give you a similar experience to a high-end NVIDIA card. Stuff like Hairworks is more of a gimmick than anything else, a marketting plot by NVIDIA to attract customers. Ngl I don't put much stock into those visual gimmicks they use to sell you stuff.
AMD have their fare share of partner games, BF4 for example.
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