I have i7 4770k and msi gaming5 z97 with 1060 msi 6 gig GPU. I play BF1 should I replace both CPU and MB with z270 and i7 7700k and keep 1060 or get new 1070 or 1080 I can only afford to do 1 or the other.
Get the GTX 1070 if you are gaming at 1440p or the GTX 1080 is you are gaming at 4k. If you are still gaming at 1080p, the 1060 is about where you want to be. I agree with the others that the i7 4770k is still a fine processor, hell I run the i5-4670k and I haven't found anything I can't do, yet.
If you're seeking max quality settings, you should get a gtx 1070. Your cpu and motherboard are perfectly fine, and the new kaby lake models aren't worth it anyways. You won't have to upgrade them for a while. Also how much ram do you have? If you only have 8gb, you should get 16gb to make it run faster.
Get the GTX 1070 if you are gaming at 1440p or the GTX 1080 is you are gaming at 4k. If you are still gaming at 1080p, the 1060 is about where you want to be. I agree with the others that the i7 4770k is still a fine processor, hell I run the i5-4670k and I haven't found anything I can't do, yet.
Be mindful that you may not get the performance you want from your new card in BF1 if that is the only reason you're upgrading. There are a large number of posts on the BF forums complaining of high CPU usage and poor frame rates across a large spread of PC setups, even some really high end rigs.