B450M Mortar 2nd M.2 slot compatibility

[crono617]

Hi all,

I am having an issue with the second M.2 slot on this motherboard. On the first slot I have a Samsung 960 EVO nvme ssd installed and it is showing up without an issue. On the second slot I tried to install a Western Digital Blue M.2 ssd (WDS500G2B0B). When I go into the BIOS this ssd is not detected and I do not see it in Windows.

Thinking I might have a defective second M.2 slot I took the Samsung EVO and placed it in the second slot. The drive is found in the BIOS and the machine boots right up.

Now thinking I might have a bad ssd I placed the WD Blue into the first slot. BIOS finds both drives, Windows boots up, and I'm able to format and use the drive.

The issue is that the first slot is the faster one and the Samsung SSD performs it's best on that. I don't want to limit the drive by keeping it on the second slot. Is there something that I'm missing as to why the WD Blue cannot be detected on the second slot?

Thanks in advance for your time.

 

[Calvin7]

M2_1 supports use of PCIe 3.0 x4 (AMD Ryzen 1st and 2nd Generation/ Ryzen with Radeon Vega Graphics) or PCIe 3.0 x2 (AMD Athlon with Radeon Vega Graphics)and SATA 6Gb/s 2242/ 2260 /2280 storage devices.

M2_2 support only PCIe 2.0 x4 2242/ 2260 /2280 storage devices

As you can see M2_2 does not support SATA 6Gb/s 2242/ 2260 /2280 storage devices such as Western Digital Blue M.2 (WDS500G2B0B).
https://www.newegg.com/Product/Product.aspx?Item=N82E16820250091

 

[crono617]

M2_1 supports use of PCIe 3.0 x4 (AMD Ryzen 1st and 2nd Generation/ Ryzen with Radeon Vega Graphics) or PCIe 3.0 x2 (AMD Athlon with Radeon Vega Graphics)and SATA 6Gb/s 2242/ 2260 /2280 storage devices.

M2_2 support only PCIe 2.0 x4 2242/ 2260 /2280 storage devices

As you can see M2_2 does not support SATA 6Gb/s 2242/ 2260 /2280 storage devices such as Western Digital Blue M.2 (WDS500G2B0B).
https://www.newegg.com/Product/Product.aspx?Item=N82E16820250091

Thanks so much Calvin7. In my haste I totally misread this in the manual. I'm really confused as to why they designed it like this though. It makes much more sense in my mind that one would put a high performing drive in slot 1 and give slot 2 the ability to support SATA. Must be a technical limitation I guess.

I'll try to find a reasonably priced drive for this slot. Thanks again Calvin!