Question M.2 running 2x instead of 4x

[Blooperboyblue]

I just recently built a system and am using a Samsung 980 pro, Asus ROG strix b550 and one SATA SSD in the first slot. My m.2 is running at exactly half of advertised speed and Samsung magician says it's running gen 4 x2. I've checked bios but it won't let me change it and I don't think it's the SSD as I was having this problem before I put it in. Not sure what would be causing it.

 

[Karadjgne]

Which M2 slot? If the bottom one, that should be pcie 3.0 and using it disables 5/6 (bottom Sata ports). The top M2 should be pcie 4.0, but is cpu lanes, not chipset, so shouldn't share with anything.

My guess is you've got a pcie setting in bios not set right, like it's set for Gen 3, which might show as pcie 4.0 x2 instead of pcie 3.0 x4

 

[Bob.B]

I just recently built a system and am using a Samsung 980 pro, Asus ROG strix b550 and one SATA SSD in the first slot. My m.2 is running at exactly half of advertised speed and Samsung magician says it's running gen 4 x2. I've checked bios but it won't let me change it and I don't think it's the SSD as I was having this problem before I put it in. Not sure what would be causing it.

Make sure you have the ssd properly installed in the slot.
Just that little extra push can make a diff.