Question M.2 Drives placement

[knght990]

I haven't built a rig in awhile, so I'm learning about new to me tech. Let me know if this question should be moved and also if there was a previous thread with this.
I noticed some motherboards have separate controllers for their M.2 slots. One via the CPU and one via the bridge. Is there a benefit or drawback in mounting the M.2 to one or the other assuming they both are the same PCIe generation?

Example board is the ASUS x570-pro TUF

 

[thecoolnessrune]

If you use M.2 through the chipset, then the connection back to the CPU must share the chipset connection back to the CPU (usually 4x lanes). With the SSD itself having the chance of using an entire 4x lanes, this means that there can be some situations of oversubscription on those lanes between the chipset and CPU when accounting for all the other stuff that is coming from the chipset.

That said, in practical use, you're likely not to notice any difference, but at the same time for practicality sake, you may as well use the lanes dedicated from the CPU when the board offers it. The lanes have already been dedicated to that purpose, and you don't have to worry about oversubscription.