[SOLVED] Gigabyte B550 does not recognize M.2 PCIE Storage

Jul 15, 2020
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I have a 2TB M.2 storage stick that I purchased for my PC. I am already booting to another M.2 stick and my board has 3 slots so I wanted to add additional storage. I have tried putting the storage in slots B and C and it is not recognized in BIOS. Thinking it might be bad I put it in Slot A and it is recognized so I know it is working...I don't see any specific settings in the BIOS to enable/disable...what am I missing? Thanks for any help...
 
Solution
Okay, that board bifurcates bandwidth from the GPU slot to the two secondary M.2 sockets. You'll see this on pg. 20 of the manual. This means the GPU will run at x8 (which generally isn't a problem). The reason it does this is so that you can use two Gen4 SSDs in those sockets (requires CPU lanes, not over B550 chipset).

So what you have to do is go to Settings menu in BIOS and under IO Ports you will see the PCIEX16 Bifurcation option - set this it 1x8/2x4. That will enable both M.2 sockets at x4 (each) and the GPU at x8. You shouldn't have to do this, the board should automatically detect, but it's a new board and BIOS so who knows. That would be my workaround.

If you're freaking out about a GPU at x8, keep in mind that...
Okay, that board bifurcates bandwidth from the GPU slot to the two secondary M.2 sockets. You'll see this on pg. 20 of the manual. This means the GPU will run at x8 (which generally isn't a problem). The reason it does this is so that you can use two Gen4 SSDs in those sockets (requires CPU lanes, not over B550 chipset).

So what you have to do is go to Settings menu in BIOS and under IO Ports you will see the PCIEX16 Bifurcation option - set this it 1x8/2x4. That will enable both M.2 sockets at x4 (each) and the GPU at x8. You shouldn't have to do this, the board should automatically detect, but it's a new board and BIOS so who knows. That would be my workaround.

If you're freaking out about a GPU at x8, keep in mind that of existing GPUs only the 2080 Ti is at all impacted performance-wise and not by a lot, and upcoming GPUs (next gen or two) will not be bandwidth-strapped by x8 PCIe 4.0.

If you want to keep the GPU at x16 you need to get a M.2-to-PCIe adapter (NVMe, not SATA) and put it in the PCIEX4_1 slot. If you use PCIEX4_2, you will lose some SATA ports.
 
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Solution
Jul 15, 2020
3
0
10
Thank you I appreciate the detailed. Response. Weird thing is in my BIOS IO Settings I don't have the PCIEX16 Bifurication setting...manual says will only show up with a compatible 3rd gen processor? I actually made a mistake when I told you my processor as AMD is replacing my 9 (long story) but right now this machine is running a Ryzen 5 3400 which appears to not be considered a 3rd gen from what I can tell so I am hoping that option will appear when I swap it with the 9, otherwise in the interim I guess I can buy an adapter....