so I'm using a PCIe 16x 4xNVMe adapter. How do I verify that each SSD is actually getting 4x PCIe?

[mrjayviper]

As above.

I got myself one of these as I need more NVMe slots than what's available in my board.

Thanks in advance for the assistance.

(image is for reference only. but mine is similar)

 

[mwroobel]

Does your motherboard support PCIe Bifurcation?

 

[vxspiritxv]

HWiNFO does exactly this...
https://www.hwinfo.com/