Motherboards and BIOS PCIe bifurcation required

sygnus21 said:

I'm still not clear on what you're trying to accomplish so...

That said, I've have two NVMe SSD's in my system directly connected to the motherboard - one being the main boot drive (Windows 10), the other being a data drive and both are accessible without issue. You can see my system specs below (system one).

Perhaps your issue is the fact that you are installing two NVMe drives on a single PCI card and installing that card in a PCI slot.

If so, why are you doing that??? Why not use one or two of the three m.2 slots on the board??? Also be aware some PCI cards won't allow an NVMe drive to OS boot off the card.

I think you need to rethink things if the current solution doesn't work or won't work.

Good luck.

I know this so far: If the two M.2 SSDs are directly installed on the motherboard, there is no problem at all. That's the first step I took.
Second step is to move those two M.2 SSDs to the external bay as shown in the photo previously uploaded, which requires to use PCIe host card plugged into x8 lane PCIe slot. This change appears to have caused Bifurcation problem.

I spent quite some times by now following the suggestions posted in this thread to trouble-shoot what is seemingly bifurcation issue.
My present thinking is if W10 installed on one of the two M.2 SSDs can be made bootable, then this is a progress. I can try connecting another M.2 SSD in the 3.5" bay to the motherboard in different way.

You said you installed the card in a x8 slot. Why do think bifurcation will work in that slot when the manual only mentions bifurcation for the x16 slot?

I expect that if you try it in a slot that does not support bifurcation then only one of the drives will be seen.

sygnus21 said:

Good catch great point.

That's what I was wondering about. But the reference shown by the link on sygnus21's post appears to indicate that bifurcation for 8 lane slot can be done by setting 16 lane slot in a particular way. But for my motherboard I could not set it exactly the same as shown in the reference. More specifically it says that if x16 slot is set for x8, then that will set x8 slot to be two x4. But x16 slot on my motherboard could not be set as x8. My understanding of what the reference says could be wrong.
I have more things to try which came up in my mind after perusing posts by everyone and will post back if any progress is made.

sygnus21 said:

Do take into account the link I posted is for "reference" and may not be the definitive answer to your issue. I mainly posted it to show how to enable bifurcation, but I also said I didn't fully understand your issue, so...

Good luck

My issue are 1)One of the two M.2 NVMe SSDs installed on PCIe host adapter is not recognized,and 2) W10 could be installed on the one detected but failed to boot. The vendor of the PCIe host adapter said the PCIe bifurcation is required. I did not do anything about bifurcation before the above 1) and 2).

Note that the M.2 devices are actually located on the 3.5" bay and they are connected to the PCIe host adapter by two cables with SFF-8643 connecter at each end. The PCIe host adapter comes with two receptacles for SFF-8643 connecters.

At this point, the issue 2) as above is most serious problem which needs be resolved before anything else.
I never used M.2 SSD. But in the process of building the new machine, I installed W10 on the M.2 device which is directly connected to the motherboard and it could boot with no issue.

sygnus21 said:

So why can't (won't) you use those on the board then? Why the insistence on using a PCIe card?

Because I need to physically access the SSDs without opening side panel of the PC case.

Additionally, MisterEd pointed out a problem that you have not addressed it. Did you even try the suggestion? What were the results?

Are you referring to the following post?

MisterEd said:

You said you installed the card in a x8 slot. Why do think bifurcation will work in that slot when the manual only mentions bifurcation for the x16 slot?

I do not see any suggestion for me to try. BTW: I already posted I cannot use x16 slot in response to Dude's suggestion.