You can boot from a Samsung 950 PRO NVMe M.2 SSD in a PCIe slot - tested with Supermicro 5028D-TN4T & Lycom DT-120 M.2 to PCIe adapter

Lycom DT-120 M.2 to PCIe adapter.

I have the 950 PRO booting Windows 10 from the PCIe slot, using the $20 adapter pictured at right. Works just the same as when it was installed in the M.2 slot. The speeds are the same. No special drivers required for the initial install, it just works. You can later add Samsung's latest driver for the best speeds.

Versatile too. Turns out it doesn't matter if I move the 950 Pro from one slot to another after the install. It all still boots up just fine, and I don't even need to alter with my BIOS settings after the relocation.

So the answer to the often-asked question:

can I boot from the Lycom DT-120 M.2 to PCIe card?

is a resounding yes!

At least when used in this SSD and Xeon D-1540 motherboard combination, using my recommended BIOS 1.0b settings, or my benchmark optimized settings, or the slightly altered settings.
Note what Samsung Magician 4.9 said, in the PCIe Slot section, Intel Xeon E7 v4/Xeon E5.
Note that Samsung Magician 4.9.5 always shows PCI-to-PCI Bridge, whether the M.2 is in the M.2 slot on the X10SDV-TLN4F motherboard, or in a Lycom PCIe M.2 to PCIe card. In other words, it doesn't know the difference, or it doesn't care.


See also at TinkerTry