Modded bios 4901, Samsung 960 EVO/250GB (boot drive) on KryoM.2 PCIe adapter w/heatsink, 2nd PCIe x16 slot, uefi boot. CSM/fast boot disabled, secure boot enabled, Samsung driver, version 2.2.
Again, thanks to all for your guidance!

thanks for that info.....
did you tried it without modded bios first is its boots?
can you pls also upload the latest CrystalDiskMark results.
also boot time from second logo ssd kicks in to windows?

i don't use CDM, as Anvil seems to be a bit more informative/consistent, though i do use their (CDM) 'info' app (CDI). i had to mod the bios for a bootable nvme volume (and to turn off CSM, GOP support had to be added to my ati gpu). boot time seems faster than the previous sata ssd, plus running server 2016 on the nvme, so control-alt-delete before desktop.

thanks