Oh, just found this info at Tom's Hardware site, concerning U.2 vrs M.2... don't have personal experience doing that...interesting. I copy/pasted his post... hope that's ok here...
"yhselp
April 1, 2016 2:32:23 AM
http://www.microsatacables.com/m2-to-u2-sff8639-pcie-x4...
It's possible - you...
This is not an easy call... +/- on both sides.
I am doing an upgrade/downsize from my 'sig rig, of which I've had the MB and CPU since April of 2011. My current Corsair 600T case is great, but I am sick of it's huge size and weight. I want the small form factor Mini ITX. The new rig I will OC...