The only reason I retired my i5 3570K build and built an i7 7700K rig is the motherboard in the i5 3570K was failing. I hate how Intel has delivered next to nothing in the past 5 years, I am sick of them and their price gouging. If AMD [Ryzen] was a mature platform I would have gone AMD.
Just a note for Gigabyte Z270X motherboards:
I looked at what you said you did to get to 5.0GHz. You probably did the following and did not mention it, so, I will state what I did on my Gigabyte Z270X-UD5. [I purchased my parts at Micro Center and the best RAM they had was Dominator 3000...