[SOLVED] M.2_2 slot does not recognize NVMe on ASUS X470i

[smemsh]

Hello, I have a Ryzen 5 Pro 3400G (part YD340BC5M4MFH) in an Asus ROG Strix X470i board with 2x 16G 2666MHz DDR4. The board has the latest BIOS revision 3004 dec 2019 applied.

This board is supposed to support dual M.2 in PCIE mode for NVMe SSDs. However, I have two 970 EVO Plus (MZ-V7S2T0B) and only the one in slot M.2_1 is recognized. M.2_2 is shown as "empty" in BIOS.

I have tried swapping the [identical] SSDs, both are good in M.2_1, but unrecognized in M.2_2, so both seem to be working. I also obtained another identical motherboard (from a different source) and duplicated the problem with that one. So this appears to be some hardware limitation.

This would seem to contradict the motherboard manual:

• p.ix: specifications summary ... storage ... M.2_1 ... (PCIe 3.0 x4 and SATA modes) ... M.2_2 ... (PCIe 3.0 x4 mode)
• p.ix: The M.2_2 slot shares bandwidth with PCIe x16. When M.2_2 slot runs in PCIe mode, the PCIe x16 will run in x8 mode
• p.1-7: [3.0 x4 supported on both M.2_1 and M.2_2]

I have set M.2_2 to AUTO in BIOS, described on p3-16 in manual, and I do not have any PCI cards installed (I am using iGPU on the 3400G). This should mean that for "the M.2_2 slot... if an M.2 device is detected, PCIEX16 will run at X8 mode, respectively" which is fine for me, and demonstrates that NVMe should be supported in both M.2_1 and M.2_2

I have tried also disabling/enabling SATA, to no effect. I have no other drives than the M.2 SSDs connected. If I try to populate only M.2_2 and not M.2_1 then the BIOS does not see any SSD at all.

unlikely that 2 different motherboards from two different sources could both have a fried rear M.2 socket, but the manual and vendor specs seem to indicate dual M.2 in PCIe 3.0x4 are supported (by sacrificing the X16 to X8). empirically I'm not finding this to be the case (with my ssds)...

anyone using dual M.2 NVMe with this board? am I missing a BIOS setting somewhere? just can't get M.2_2 to recognize anything for either of these boards I'm trying with.

 

[Nick-M]

try setting nvme raid mode on

 

[Nemesia]

You should check if the the second M.2 is seen in Windows.

 

[smemsh]

try setting nvme raid mode on

tried that, no effect. SSD still not seen in slot M.2_2. confirmed again just now.

 

[smemsh]

You should check if the the second M.2 is seen in Windows.

I can confirm the operating system sees only the M.2_1 also (booted from installation media)

I also just now tried with a different model 970 EVO (non Plus) MZ-V7E2T0 in the M.2_2 socket and still nothing. I would just assume it's the motherboard except the second board acts the same way...

hoping to hear from someone successfully using this board with any model dual NVMe and not just dual M.2 SATA (which I suspect would work but don't have any to try)

 

[smemsh]

I discovered that using an APU takes some of the PCIe lanes that would be used for M.2_2, so only one M.2 is supported in such configurations. If I had used for example a 3600 instead of a 3400G the second M.2 should work (I don't have one to test).

to workaround, the x16 GPU slot was unused since I have the iGPU, so those lanes are free. I was able to use a $15 x16 slot to M.2 3.0x4 riser and it's working fine, both drives are visible now.