Z170 Deluxe with M.2 question

[phillyman36]

For those with Asus Z170 mobo I have a question. I just got a Samsung 950 Pro drive. I installed it in the M.2 slot. In the Z170 Deluxe bios under the Onboard Device Config then Sata Mode Config I set it to M.2 instead of Sata Express. However when I reboot and check the bios it switches the m.2 mode back to Sata Express. When using an Nvme M.2 drive shouldn't is be set to M.2 and not Sata express?

 

[Deders]

Was confused about this myself for some time, but it is behaving as it should.

The 950 Pro is a PCI Express based drive so it doesn't use sata express, and therefore doesn't take up any of the sata lanes when installed.