@crucifier - thanks, I will check them out. Manually being able to change doesn't need to be possible for user, but actually having the setting within the BIOS (Hidden) is a must, so I only wanted to see how/where it's implemented

Zitat von Lost_N_BIOS im Beitrag #16

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@crucifier - thanks, I will check them out. Manually being able to change doesn't need to be possible for user, but actually having the setting within the BIOS (Hidden) is a must, so I only wanted to see how/where it's implemented

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Yes, I agree, but if there's not even BIOS setting hidden then we know it's probably not possible or at very least will be difficult to add/enabled

@crucifier - bios-mods link does not show anything, only user asking Asrock and them giving generic response (of no actual response indicating anything is enabled/possible)
[H] forum thread makes it sound like per the chipset specs this is possible at that level, nothing else Asrock specific except them "Not" implementing it. So seems like you haven't linked anything showing this is enabled on any Asrock board, more-so the opposite I think
I'll check MSI BIOS shortly - nothing visible or hidden for lane width or bifurcation in MSI Z97 Gaming 7

If we can uncover what register controls this bet you can do it via the command line and make a batch file

hello, thank you for join the discussion

Asrock users telling about bifurcation support in beta BIOS, but I checked beta BIOS section for some boards inside BCP and still no hidden settings in it.

Asus z97-a mobo sets bifurcation configuration automatically between x16 and x8x8 if second x16 pci-e slot has card installed. And I'm wasted 4 pcie lanes for using it for second NVME disk.
As it doing automatically I think there is no possibility to set controll register statically it will be overwrited during POST. But if it possible to mod BIOS to set x8x4x4 instead of x8x8 it can solve my problem.


The z97 chipset documentation link:

https://www.intel.com/content/www/us/en/...-datasheet.html

CPU Haswell documentation:

https://www.intel.com/content/dam/www/pu...1-datasheet.pdf

CPU documentation in secion 6.3. tells that CFG[6:5]: controls PCI Express* Bifurcation. This is physicall pins on socket which should be set to 1/0.

[Guide] - How to Bifurcate a PCI-E slot

I'm already experimented with it, but no luck. Nothing changed in hwinfo. May be it can't be done this way, maybe I didn't do it very well.

@crucifier - that is why I asked, please link some board or BIOS you know this is in so we can check. If there is discussion of some beta, link that BIOS, it may not be on regular motherboard download page, you'll have to find it where they are discussing it.

I think what you mean, normal lane split for SLI/XFire is not same thing as bifurcation. Maybe it is and I'm thinking about that wrong?

I see these options at ME @davidm71 - do you think changing here helps anything (Default in blue) I'm digging around in assembly right now @AMITSE and Setup, but nothing looking interesting there, maybe since non-optional in BIOS I need to look at some PCH or SA module instead.

I'm using this BIOS:
[OFFER] ASUS Z97-A updated BIOS

it's doing x16 to x8x8 without any manual settings.

Zitat von Lost_N_BIOS im Beitrag #21

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I think what you mean, normal lane split for SLI/XFire is not same thing as bifurcation. Maybe it is and I'm thinking about that wrong?

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That's normal for PCIE slots, even P35 and earlier did that, I don't think that is same thing unless I'm reading you wrong. Do you mean If one card is in slot 1 it's x16, then if you connect second card in slot two, both slots become x8, is that what you mean?
If yes, I think that's not the same thing as an individual slot becoming x8x8 or x4x4x4x4. Or did you really mean from a single slot you are getting x8x8 across two drives?

Zitat von Lost_N_BIOS im Beitrag #24

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That's normal for PCIE slots, even P35 and earlier did that, I don't think that is same thing unless I'm reading you wrong. Do you mean If one card is in slot 1 it's x16, then if you connect second card in slot two, both slots become x8, is that what you mean?

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I thought that's what you meant the way you mentioned it, that isn't bifurcation, at least not in the way we're talking here. Bifurcation is on a single slot only, not changing whether it's x16 or x8, but making one single slot x8+x8 by itself (So still x16) or x4+x4+x4+x4 (still x16 total)

PLX Chip is normally used to add more lanes than the CPU/Chipset has, for SLI/Crossfire, this isn't added for bifurcation either, but I supposed it could be used in that way.
@paranoid_android was having issue with bifurcation on P9X79 due to PLX, I think, or at least it was messing with things more-so than his other similar board without the PLX

So, you don't know any BIOS from Asrock or MSI from Z97 that you've seen someone confirming bifurcation for PCIE SSD's?

here is the source of my opinion:

https://www-ssl.intel.com/content/www/us...ation-demo.html


No, I can't find any direct link for z97 with manual bifurcation settings in BIOS.

Zitat

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LX Chip is normally used to add more lanes than the CPU/Chipset has, for SLI/Crossfire, this isn't added for bifurcation either, but I supposed it could be used in that way.
@paranoid_android was having issue with bifurcation on P9X79 due to PLX, I think, or at least it was messing with things more-so than his other similar board without the PLX

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I think it act as a hub and can't to add any lines, only split one x16(for example) device to several devices with less bandwith.
But PLX can do it without any cpu, chipset compatibility issues.


IMHO

Zitat von Lost_N_BIOS im Beitrag #21

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I see these options at ME @davidm71 - do you think changing here helps anything (Default in blue) I'm digging around in assembly right now @AMITSE and Setup, but nothing looking interesting there, maybe since non-optional in BIOS I need to look at some PCH or SA module instead.

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Thanks @davidm71 - I guess only way to know is try changing some things That is Intel FITc, from the Intel ME System Tools packages, that you do the ME clean/transfer with from the ME Cleanup guides and ME Drivers/System Tools thread.
Does any of the others look like they'd be ideal, aside from the one highlighted in blue (That's the default applied value)

@crucifier I thought you said you knew users/threads where this was being shown, discussed, used etc on Asrock/MSI Z97 boards?
I've not seen it possible on Z97, but people don't often look into this on older boards either, but they few I've looked into lack the basic BIOS necessities to enable.

Hello, friends

Thank you for your attention to my request for help.
It is very interesting to dive into the BIOS functionality and configuration, but in this particular case it is not economically efficient.
I'm going to buy a used motherboard with an additional slot and support for x8x4x4 bifurcation for $ 50-80, that will be easiest way.