I was watching some comparisons of the i7 2700k and the i7 3770k, and it noticed that there's supported memory frequency involved. I was wondering, will a 1.5v 1866Mhz 16GB 2x8 RAM work with my i7 2700k fully functionally? Thanks.
No reason why they wouldn't. You can always use bios settings to tweak RAM and CPU clock frequencies to find your sweetspot. As long as your RAM works at 1.5v that you state, you'll be ok.
In my previous build I had an i5-750 running at 3,8ghz with 2X4gb RAM@1600, even though intel says 1066-1333 were supported. It never failed me.