[REQUEST] BIOS mod for Z370I Gaming Pro Carbon AC / PCIE Bifurcation

Hello all.
I am trying to use PCIE x16 (4xNVME) adapter on my Z370I Gaming Pro Carbon AC mobo. I am trying to use it as nas storage and one thing left is to use this adapter.
To achieve that I need to use PCIE x4/x4/x4/x4 bifurcation that I could not find anywhere in the BIOS. I have used UEFI Editor to see if this is even possible but I was lost at some point.

Could you please help me with this? I would like to know if that’s possible because if not - I will need to change my plans for this home server project :).
Thank you very much in advance for any reply!

BIOS I use:

It’s my first post here - so I want to say Hi to everyone :wink:

You can’t, unless your adapter has a BIF lane switch IC on it, not cheaper these ones…
Or next time do not buy an ITX board…
All the best, good luck.

EDIT: I’ll add an example of what you want, but this concerns Asus and specific bios settings for their Hyper M.2x16 Card on the Strix Z370i.
And ONLY using Intel disks…
I don’t recall to see any of this, besides high-end like the Zxxx GODLIKE, using any MSI M.2 XPANDER Cards on non-HPerformance chipsets like the Intel Xxxx series


Thank you for your reply.
I have the card from the link below. The card supports it as I was able to fully utilize it on Gigabyte Z590I AORUS ULTRA.

I did not want to use newer mobo for this project that’s why I used older one.
And the vendor lists many Z370 motherboards that they tested and are able to use it.

That’s why my request to check the bios originated from. Maybe it’s suppored but the option is hidden.

Ali Link

Present in the Z590I AORUS ULTRA, these are in bios code, CAN’T confirm visibility to user on regular motherboard function to be visible in bios.

The Z590 is a more advanced “Old Skylake” chipset called Rocket Lake with much more bios settings and usually has the option you’re looking for on the primary PCIex16 slot as 8x8/4x4x4x4, this is not present on your Z370 bios and not hidden also.

The PCIe adapter you linked does not have Bifurcation support IC on it, it requires a motherboard with it, that is not the case in your Z370.

Here 2 examples of PCIe M.2 with Bifurcation embedded on it, not requiring motherboard with bios lane split:
Dual Slot M.2 NVMe PCIe 3.0 X4 Adapter Card with ASM 2812 PCIe Bifurcation Function, Work with None PCIe Splitter Function Motherboard (glotrends-store.com)
Dual M.2 PCIe SSD Adapter Card NVME/AHCI - Drive Adapters and Drive Converters | Hard Drive Accessories | StarTech.com Europe

That’s it, you can wait for another user pov, all the best and good luck.


Thank you for such a comprehensive comment. In that case I will just change the CPU for Z590 to get iGPU and use Bifurcation there. You helped a lot! Thank you again! :slight_smile:

@MeatWar Could you please tell me your POV about Z590I AORUS ULTRA (rev. 1.0)? I have double checked it and it has x8/x4/x4 but is it possible to mod it to x4/x4/x4/x4 ?
Info from manual:

I would really appreciate it.

I can’t confirm anything more than what already posted, i don’t have such a model to see it live (VISIBILITY). Search on the web for reviews and maybe you can find screen caps of bios menus.

On the user menu in BIOS it is as in the manual:

  • Auto
  • x8/x8
  • x8/x4/x4

And I can confirm that I can see 3 out of 4 disks on teh controler.



This suggests that the option (x4/x4/x4/x4) can be enabled or is hidden from the user or it’s just not possible?