Aorus B550 Pro m.2 Issues

[HotTowels]

I'm doing a new PC build, and I went with two m.2 SSDs. Both 1TB, one is PCIe gen4 and the other is PCIe gen 3. When the gen 4 ssd is in the gen 4 slot, and gen 3 ssd is in the gen 3 slot, the motherboard doesn't seem to recognize both. However, if I switch the two, they both show up in the BIOS. 

That obviously defeats the purpose of having paid the premium for a PCIe gen 4 m.2 ssd, so I'm hoping that's not the solution. 

I know that in the motherboard's manual, it says that if there's an m.2 ssd in the gen 3 slot that the neighboring PCIe gen 3 x4 slot is disabled, but that's not a problem as the only other thing plugged in is the GPU in the PCIe gen 4 x16 slot. 

 

Any ideas as to what I'm missing here? I've searched through the BIOS but I'm not seeing anything promising. Cheers!

 

 

[HotTowels]

1 minute ago, BlueScope819 said:

On B550 you have a limited number of PCIe lanes because it's 3.0 speed coming from the chipset so try and plug in just the 4.0 one and the GPU and see what happens.

I've only got the one 3.0 m.2 ssd going through the chipset, if I understand b550 correctly, it should then accommodate the 4.0 m.2 ssd and 4.0 GPU just fine, since those go directly to the processor.

If either SSD is in the 4.0 lane, they're recognized. However, both are only recognized at the same time when the gen 4 m.2 ssd is in the 3.0 slot and gen 3 m.2 ssd is in the 4.0 slot. 

[HotTowels]

6 minutes ago, BlueScope819 said:

Interesting. If you check on your motherboard manual does it tell you how it allocates PCIe lanes?

Yeah it does, this is from the product page and reflects what is in the manual.