New CPU or new GPU?

Elementalfury

Honorable
Dec 28, 2015
299
0
10,780
I have came to a predicament in if I should get a second GPU or a new CPU. The choice(s) are that I get a second 970 Geforce gtx strx, or that I get myself a new Quad-Core i7-6700k intel processor, also I currently have a Gaming 5 MSI motherboard aswell. Any sort of feedback would be helpful, thanks!
 

Elementalfury

Honorable
Dec 28, 2015
299
0
10,780
Forgot to mention that I HAVE a i5-490k. Seems a little odd upgrading an already good build, but I was recently playing Ghost in the Shell: First Assault, and my FPS seemed to be jumpy for such a low demanding game spec wise. So I'm a little curious on a way to get my games to be a little more consistent, as well as being ready for the multiple bigger games coming out later. Anything on fixing that would be appreciated