11 minutes ago, fluisterben said:

The x16 slot now has a card with 3 M.2 NVME SSD's, and the manual says the x16 slot will auto-switch to x8 when that (other) x8 slot is occupied. Not sure if the ssd card is using the full x16 bandwidth. Will have to check..

This will be interesting, I guess after insert the card, 3 M.2 would only detect 2 instead 3. ( You may verify by insert any PCIe card )

Edited July 11, 20197 yr by Benson

9 minutes ago, Benson said:

This will be interesting, I guess after insert the card, 3 M.2 would only detect 2 instead 3. ( You may verify by insert any PCIe card )

I don't think so, the PCI-E x16 slot is already set to x8/x4/x4 mode in BIOS. Check this mail correspondence I had with ASRockrack about it;

 

> -----Original Message-----
> Subject: RE: #ULTRA QUAD M.2 CARD# compatibility motherboard 
>
> Hello,
>
>> My colleague from ASRock Rack borrowed me an E3C246D4U.
>> The bifurcation settings that are available for the PCIe 3.0 x16 slot are:
>> X16
>> X8/x8
>> X8/x4/x4
>>
>> As far as I can tell, the C246 chipset does not support x4/x4/x4/x4.
>
> Is this not fixable by a workaround in BIOS?
> Or truly a strict limitation of the hardware for C246 ?
>
>> I tested with an Ultra Quad M.2 Card on this motherboard, filled with
>> 4 NVME
>> M.2 SSDs.
>>
>> Set PCIE6 Link Width to x8/x4/x4.
>>
>> As expected, 3 out of 4 SSDs were detected (sockets M2_1, M2_3 and
>> M2_4 on the Ultra Quad M.2 Card).
>
> OK, so I can run 3 of the 4 slots. At least that's something.
> I was not aware of such strange limitations for a very current Intel chipset.
> I truly don't understand these manufacturers of chipsets.
> Why would you create support for x8/x4/x4, but not x4/x4/x4/x4 ?
> Seems to me that's just some strange management decision, not an 
> actual hardware limitation.
>
> But hey, thanks a lot for this valuable info!
>
> Regards,

Hello,

I would think it is an artificial limitation built into the 
chipset/CPU, to differentiate between different price ranges/classes.

To be sure I have asked ASRock Rack R&D to check. When I get a reply I 
will let you know :)

Kind regards,
ASRock Support

 

If bifurcation haven't 4444 option, then 1 M.2 should be detect if other slot insert a card, like a quad M.2 card can use three M.2 currently.

Edited July 12, 20197 yr by Benson

18 hours ago, Benson said:

If bifurcation haven't 4444 option, then 1 M.2 should be detect if other slot insert a card, like a quad M.2 card can use three M.2 currently.

That would be the case if it was logical division (x8 and x8 bandwidth divided over the x16 + x8 slots), but I don't think it is. I'll let y'all know what it ends up doing.

On 7/12/2019 at 5:11 PM, fluisterben said:

That would be the case if it was logical division (x8 and x8 bandwidth divided over the x16 + x8 slots), but I don't think it is. I'll let y'all know what it ends up doing.

Hi - any update on this?