Should I upgrade my cpu if I am upgrading my gpu?

Crazylukas33

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Aug 12, 2015
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System Specs:
core i5 4670s @3.1ghz
EVGA gtx960 4gb gddr5
16gb ddr3 RAM
ASUS z97 D3H mobo

I saw that Nvidia recently showcased its newest products: the gtx1080 and the gtx1070. I would love to buy either one of those graphics cards to replace my 960. If I purchased one of them, would I also have to upgrade my cpu to avoid bottlenecking? Or can I just upgrade my gpu by istelf?
 

Crazylukas33

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Aug 12, 2015
14
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4,510




I'll be playing games on ultra that require a pretty beefy system like dying light, fallout 4, killing floor 2, arma 3, etc. Would that possibly change anything?