Does the ASRock D2143D8UM motherboard support PCIe bifurcation?

[Mannekino]

Hi,

Does anybody know if this motherboard supports PCIe bifurcation https://www.asrockrack.com/general/productdetail.asp?Model=D2143D8UM#Specifications

I would like to use a dual of quad M.2 adapter card in one of the PCIe slots. The manual doesn't say anything other than this:





I've seen in some screenshots of other ASRock motherboards that there are options like 4x4x4x4 for this setting, but the manual doesn't say anything about the possible values on this particular board.

Thanks!

 

[RolloZ170]

can we have the BIOS file ?

 

[Mannekino]

I found a BIOS file in another thread on this forum. I have also sent ASRock an e-mail asking two questions:

• Does the board support bifurcation?
• Can I have the most recent BIOS and BCM files?

I sent it to asrockrack_eu@asrock.nl but I don't know if that is a valid email address, I haven't received a reply yet.

This is the most recent BIOS I found on this forum: BIOS file 1.09

 

[RolloZ170]

this setting should work, but must not..

 

[Mannekino]

I don't understand what you're trying to say. You say it should work but must not... must not what? I don't get it.

 

[RolloZ170]

You say it should work but must not... must not what?

you can write anything in the BIOS.
even is you set to x4x4x4x4 this must not supported/implemented in the processor init. code.
i have seen similar many times.

 

[Mannekino]

Hmm, so you're saying it definitely won't work?

I don't have the server yet. I ordered it yesterday should be getting it in 1-2 weeks or so. I might be interested in using one of those PCIe to quad M.2 adapter cards with PCIe bifurcation.

So If I want to do that I would have to get one of those expensive ones with a controller chip on it to split the PCIe lanes.

The server has this CPU installed: Intel® Xeon® D-2143IT Processor (11M Cache, 2.20 GHz) - Product Specifications | Intel

 

[RolloZ170]

Hmm, so you're saying it definitely won't work?

no. I don't want to make you any promises.

 

[Mannekino]

Alright, when I get the server I will check out the BIOS and see what kind of options I have. If I see that x4x4x4x4 one I will buy one of those cheap PCIe 3.0 to quad M.2 adapter cards to test it.

Thank you for helping me.

 

[RolloZ170]

i am careful because Slot4+6 is supllied by only 16 PCIe lanes. PCIe Slot4 over a Switch.
x4x4x4x4
can mean
Slot4 x4x4
Slot6 x4x4
or
Slot6 x4x4x4x4
Slot4 disabled

 

[Mannekino]

Ah yes, in the manual it says this about those slots.



So, it would make sense if you only populate slot PCIE6 with one PCIe 3.0 to quad M.2 NVMe card all the 16 PCIe lanes would go to that slot and when you set it to x4x4x4x4 all would go to PCIE6.

No other way to know than to test it when I get the server I guess.

 

[Skillz]

On an AMD based AsRock motherboard (asrock rack epycd8-2t) the Bifurcation settings are located at:

advanced > Chipset configuration >

 

[Mannekino]

Yeah, I'm pretty hopeful it's the same on this board but it's just a bit weird because the PCIe lanes are shared between both slots with a switch.

I think there's a good chance the x4x4x4x4 setting will split the PCIE6 slot to that mode.

 

[Skillz]

This is one reason why I went AMD. Lots more PCIe lanes than Intel's offerings.

 

[Mannekino]

For sure, but this server I bought and this board are perfectly suited for my need. But more PCIe lanes would have been nice for future expansion. But I'm very happy. Looking forward to receiving the server in a week or so and then building a kickass TrueNAS SCALE server with it. Gonna take some creative modding to transplant it in a normal case with a new CPU cooler.

 

[Skillz]

Wasn't trying to knock you on your purchase. Was more or less just expressing that AMD has more PCIe lanes than Intel usually does. Which might be why the AMD boards have better support for bifurcation than Intel boards. I'm sure that server will be very good. Those old Xeons still have a lot of life left in them depending on what they're used for.

 

[UhClem]

Alright, when I get the server I will check out the BIOS and see what kind of options I have. If I see that x4x4x4x4 one I will buy one of those cheap PCIe 3.0 to quad M.2 adapter cards to test it. ..

Seeing the option in the BIOS is maybe a good sign. (the screenshot that @RolloZ170 posted for the actual BIOS you linked IS very likely what you will see when you actually enter the BIOS on boot). But that is not a guarantee that it will actually be implemented in the real BIOS code and/or at the hardware/mobo level. We've seen it before--even from Supermicro.

Before you buy any bifurcation-dependent card, you can TEST things by putting any PCIe x8 (or x16) card into slot6. Choose the x4x4x4x4 setting in BIOS. Boot your OS. On Linux, IF the setting actually took effect, the (voluminous) output of lspci -vv will show (under data for that card in slot6) a LnkCap: with x8 (or x16), BUT a LnkSta: of x4 (downgraded).

Repeat for slot4.

... and then building a kickass TrueNAS SCALE server with it

Forget about a bifurcation-dependent QUAD card in slot6. Where are you going to put an HBA? (I don't see 4x M.2's kicking any ass w/ZFS )
====
"Where's Goshen?" ... "You can't get there from here."

 

[Mannekino]

Forget about a bifurcation-dependent QUAD card in slot6. Where are you going to put an HBA? (I don't see 4x M.2's kicking any ass w/ZFS )

I'm not planning on using an HBA in this build. I'm going to use two SFF-8643 to 4x SATA breakout cables and use the onboard headers.

 

[UhClem]

I'm not planning on using an HBA in this build. I'm going to use two SFF-8643 to 4x SATA breakout cables and use the onboard headers.

View attachment 26491
...

Good point.
And, if/when it's time to seriously kick butt, you can add an M3008.
And, further on, when 10GbE is slow, you can remove the QUAD, and replace it with a 40Gb (or 100Gb) @x8 (slot6), and, when ZFS has evolved into fully-integrated multi-tiered storage, a 4x U.2 (on real PCIe_switch) card @x8 (slot4).
=====
"How do you like the Future?" ... "But the future's not here yet."

 

[jb6574]

Ah yes, in the manual it says this about those slots.

View attachment 26485

So, it would make sense if you only populate slot PCIE6 with one PCIe 3.0 to quad M.2 NVMe card all the 16 PCIe lanes would go to that slot and when you set it to x4x4x4x4 all would go to PCIE6.

No other way to know than to test it when I get the server I guess.

Did you ever manage to get bifurcation working on this board? I'm having trouble with a x8 card and two NVMe drives, no matter which setting I use in the BIOS...