The "compatibility" from Crucial is simply a guarantee that if it does not work, you can send it back to them. They don't test with all these system configurations. I have seen them mark DDR 4000 compatible with these systems...  
Recently put 2x16gb 3200mhz cl16 crucial ballistix ram in my r10 works great. Thought I would manually set the speed to see how far it would go. 3400mhz works great as well. Now 3600mhz is where things gets interesting.  The pc boots right up and everything works fine.  Then I start to do some checking.  Alienware command center shows 3600mhz as does cpuz, hwinfo and aida64.  Task manager shows nothing, but alienware bios shows ram speed at an insane 65535mhz. Then checking windows through the command prompt with "wmic memorychip get speed" it says 2667mhz and so does memtest64.  Running benchmarks from pass mark and aidia 64 are showing increased performance going from 3400mhz to 3600mhz.  So I guess what I am trying to get at here is the ram really running at 3600mhz or 2667mhz like windows says?  Could the 2667mhz showing in windows just be a glych along with the insane number shown in bios because there is no support for 3600mhz in the r10?
Aurora R10, Crucial Ballistix 2x16GB 3200MHz, run at 3600MHz