Just to give you an idea, apparently the Nvidia card, which sits in PCI slot 1, turns out being Root port 3a IOU1
and Root port 2a says it has full x16 bandwidth, but all sub-PCI's only state x8. Weird design. I'm afraid it's not going to offer x4x4x4x4 anywhere in this case (especially in this case).
(ignore all currently connected devices, they're leaving this board, except for the GTi1080..)

The BIOS;

and the board's diagram indeed seems to tell me I should occupy PCIE1, PCIE5 and PCIE7, and nothing else:

Zitat von drevilish im Beitrag #31

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I have a ASUS X99 SABRETOOTH
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I ordered an ASRock Quad m.2 card to put in the x16 Slot 2 (x8) works great but only the first m.2(1) port works because of bifurcation.
...
PCIe Slot 3 is already bifurcated on this board.

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@iushe618749 - what you see as default/optimal is what is applied when you load optimal defaults, so if you are looking at the correct slot then that is what will be used

Does anyone know how to do something similar for a Ryzen board please?

I opened a thread here Attempting to enable 2x8 bifurcation in MSI B450 ITX Gaming Plus AC

I tried to open latest bios for msi X99A gaming 7 and I got following error 7885vHH2 (https://download.msi.com/bos_exe/mb/7885vHH2.zip) however if I open old bios version 7885vHF (https://download.msi.com/bos_exe/mb/7885vHF.zip) it is working. Please help in getting latest bios working with AMIBCP tool. I checked online but find info to delete modules, I am not sure if that will be a good idea.

Please correct me if I am wrong that after changing settings the way I want I need to save file with a new name and flash it correct ?

I also get that with ru.exe method we can try changing settings of bifurcation in current bios without flashing until we reset bios settings is my understanding right?


Language name present in the ROM file exceeds 0x08 in length. Setup tab and BIOS Strings tab will not be shown.

@demail2006 - I can possibly make you mod BIOS with IntelRCSetup section visible in BIOS if you want? If you want that, please make a new thread and I will get started helping you on this.

To answer your question, yes, you remove modules until you find the problem one, then you can open in AMIBCP, but this takes hours/days and is not ideal.
No, if you had a working AMIBCP version for that BIOS, you'd make changes you want, then same with same stock BIOS name.extension and then flash with M-Flash.

Thank you for your reply....!! :)

I made changes in bios file and saved it and flashed it. When I flash with M-flash it shows my bios with new date and flashes it but when system reboots, It show the original BIOS build date and changes are not there.... :( I don't expect to behave it like that. Please help if you know or have any Idea what can we do here.

I will soon make a new thread for this motherboard pcie bifurcation.

Thank you very much for the guide finally I got the bifurcation working. I got that what BIOS build date it is showing is nothing to do with pcie bifurcation. First tried with all slots set to x4,x4 or x4,x4,x4,x4 modes and in the both optimal and fail safe settings, Then I dialed back to auto for the slot I need bifurcated. I find out that maybe hwinfo and bios tool show cards in reverse order, Hence I was not able to achieve it earlier.

However I done it on old BIOS, I will be grateful if I get Any help to achieve same on newer BIOS. Is there a chance if there is a newer AMIBCP tool available which can open newer BIOS files without error?

I have one request. Please let us know how can we get the setting option bios for set PCIE Bifurcation Support like screenshot in following thread.

https://www.techpowerup.com/forums/threa...eration.240074/

Zitat von davidm71 im Beitrag #8

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Just wanted to add a couple tips to this guide as far increasing the chance of success as it isn't just enough to turn on bifurcation by setting the port to x4x4. It still may not work or sync properly or need more time to sync so there are a few settings you can try changing.

1. Extended sync mode : turn on
2. Link Retraining retry : set to max
3. Link Training Timeout: change from a 1000 to 10000 (in hex would be 2710 or 1027 in proper reverse order at offset x26E)

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Is that possible to use one PCI-e x16 for graphic and another PCI-e x16 like 4x4x and install asus hyper m.2 x16 card with two or four nvme drives in raid0?
I already added nvme booting to Asus Z87 Gryphon (bios 2103) and im wonder if i can use asus hyper m.2 x16 with two or four drives in raid0 using bifurcate on Z87

@Dabman, it is possible to use a PCIe×16 with an Asus Hyper M.2×16 Card or an Asrock UltraQuad M.2 Card.
I have one Asrock running in my C602 System, on a bitfurcated ×16 slot, set to ×4×4×4×4. two m.2 ssds are currently mounted, but in single drive use.
Use in a Raid Array might be possible, but limited tp a software raid only. My CPU does not support Intel VROC.
Additionally, I have an Asus Hyper M.2 running in a X79 system, on a ×8 slot set to ×4×4.
I can make use of the first two m.2 slots only.

But I have no idea if any setup or configuration like the above would work with a Z87 chipset.
Z87 and its respective CPUs support only one PCIe Root Port. That means 16 PCI-Lanes from CPu only.
If your MB features more than one PCIe×16 slot at all, it is very likely that all of the MBs slots are shared or managed by a PCI switch.
As I understand so far, only the Root Port Resource itself can be bitfurcated in Bios.

The enthusiast and server platforms like X79, X99... C602, C612 and the respective CPUs feature 3 Root Ports, two ×16 and one ×8 (later models feature a third ×16).
These can either be linked to MB slots directly or be split or shared to PCIe slots of varying widh.
If you could unlock a BIOS option on a Z87 chipset MB allowing bitfurcation, it would mean that you qould split the sole ×16 Root Port wich also provides for the MB graphic card slot.
To manually bitfurcate the Z87s PCIe root port other than the vanilla layout allows may not be possible at all, but I'm no expert...

@Lost_N_BIOS
@JackSted

I have encountered a new problem concerning the bitfurcation mod bios images I git from you (Don't know who made the final one anymore):
I had applied the image files for my P9X79-WS and P9X79E-WS boards and looking the options up in the bios setup screens, the modifications seemed to work.

At that time I had set the P9X79E-WS's IOU Port1 (sole PCIe×8 Slot) from "×8" to "×4×4".
I had attached a PCIe× USB Card to that slot at that time, so the change would not have a practical use.
However, after apllying the setting and booting to windows, HW Info showed two Instances of the IOU 1 Port both at ×4, one of them being relatet to the PCIe×4 card.
So I was expecting that the mod was functional.

Now, I have had the oppertunity to mount an Asus Hyper M.2 Quad Card to that ×8 slot.
The Card is ×16 wide but fits the slot, which is mechanically ×16.
I had mounted 2 NVME SSDs to the card, on M.2 slots 1 and 2.
After booting up Windows, only the first card was displayed by the System, the Device Mangager, as well as by HWInfo.
The IOU 1 Port was now displayed only once, as a ×16 port linked down to x4.
No sign of the bitfurcation.

I entered the Bios setup menu again and I realized something that was present before, but overseen or misunderstood by me:
Wether I had set one or any of the IOU Ports to bitfurcaton or not, still the link speed options for EVERY sub-port (1A, 1B, 2A, 2B, ... 3D) were displayed.
So it became clear that the menu options had been made visible, but to no practial effect.

I looked up the bios setup menu of the "smaller" Board, the P9X79-WS, and it was the same there.
Though it has a different distribution of Ports and Slots, the link speed options for any possible Port were shown, in contradiction to the bitfurcation settings, which were all ×16 or ×8.
The options for Root Ports 2 and 3 were shown as if they had both been split to ×4×4×4×4, disregarding that each of them was still set to ×16.

Guys, I'm calling you for help to look over those files again that we exchanged. Is that possible?

Try all slots on the card, and then also try same on your Asrock card instead, to rule out Asus incompatibility with it's own hardware Also, confirm on other board, or this one, that all slots work on your hyper card one at a time.
Link speed has nothing to do with lane width, link speed will always remain what you set it to (PCIE 2/3 etc)

Further than this, JackSted will have to help, I don't have any of these boards to figure this out on, but I assume it has to be some confusion on slots/settings and what's what (or what I mentioned above)

@Lost_N_BIOS ...

I wil try out the Asrock and Asus Card vice versa in both boards.

Why I was suspicius about the apperaing "Link Speed" options:
In the Z9PED8-WS's setup, these options are made available only for activated ports.
So, if I have set Root Port 2 to ×16, Only One sup-option for Link Speed is available:
"PORT2 LINK SPEED"
If i set Root Port 2 to 4×4×4×4, additional sup-options appear:
PORT2A LINK SPPED
PORT2B LINK SPEED
PORT2C LINK SPEED
PORT2D LINK SPEED

In X79E-WS's modded bios setup, all these options appear by default for every port, no matter if bifurcation options are set or not.
That's what I found a bit distracting and made me think that the whole mod would have no function.