The system is using a Gigabyte GA-X99 Gaming G1 motherboard. I'm using a 1.2 TB Intel 750 as a data drive. I just got a P900 Optane to replace an older Samsung 840 EVO SSD.

I cloned the SSD to the P900 and disconnected the old SSD. The P900 boots into Windows 10 just fine on its own.

But as soon as I add the Intel 750 back into the system and boot it up, the Gigabyte UEFI clears the BIOS splash screen, goes black, and never does anything else.

I'm using the Intel recommended UEFI settings with Other OS, CSM on, UEFI priority.

I suspect, but don't know, that the UEFI NVMe drivers for the Optane and the 750 are conflicting, trying to claim the same hardware.

I'm hoping someone has a solution for this. Otherwise I may have to disable CSM and see if I can rig up a boot EFI partition on a flash drive or something.

  • I don't think its NVMe. Because you have CSM on it might be that its trying boot the Intel instead of the Optane. Can you confirm that the intel is in the boot priority? – jdwolf Nov 22 '17 at 6:45

AFAIK UEFI scans hardware on boot and readjusts its device list (and bootable device list).

I would check that data drive (Intel 750) has no EFI System Partition(ESP) so it cannot be listed as first boot candidate. (Assuming UEFI boot first then CSM/BIOS order).

I have observed strange Windows behaviour on a system with two disks, each with its own ESP (+ MS Reserved partition) and Windows installation.

It's always best practice to have only one ESP on a multi disk system and the ESP placed on the fastest disk attached as first physical disk, so there cannot be any confusion for ESP place and order.

UEFI firmware implementations are not perfect as we can see on many forums ;)

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