Intel Motherboards : How To Install Windows On A PCIe SSD

 

This statement in your main discussion is fiction and you can't prove it.  It is also 100% wrong!  The statement I am referring to is this: "The Windows NVMe driver is known to have write performance issues, which I noticed when installing Windows 10 on a 950 Pro. That installation was much slower (five+ minutes) than installing Windows 10 on an AHCI SM951 (three minutes at most.)
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There are DESIGN differences with the ACHI miniport and NVMe miniport.  ACHI (in-box) doesn't honor FUA (Forced used access (means bypass cache and hit the physical media (flash in this case.))).  NVMe does. 

So the check box in device manager-> disks -> "some disk you select" and then 'properties', then the 2nd tab and then the bottom box (if shown).  Most often there are two boxes.  First one is WCE for the device.  Second is FUA support (unchecked yes, and miniport supported); checked 'FUA' can be ignored.

So I hope  you remove the paragraph now that you have been enlightened.

It just so happens the Samsung has higher write completion latencies (time) when directly writing to the flash.  I guess the firmware really takes advantage of the onboard DRAM cache (the M.2 card) for writes and GC (garbage collection/ wear leveling.)

Also the drive isn't' setup for over-provisioning and per Samsung this can improve performance.  I have not tested that claim.