Originally Posted by Sin0822
I don't think any Z370 motherboards have M.2 slots routed to the CPU directly, they are, for the most part routed to the PCH, which has 24 PCi-E lanes. So no, you can even install 3x x4 PCI-E 3.0 M.2 drives and not interfer with your CPU's x16 for GPUs.
This is correct.
once you settle on a board you would like. Reference the manual most companies include a PCI-E layout or explanation for the M.2 drives.
For example on the Gigabyte Z370 Gaming 7 has 3 M.2 slots. Top slot has dedicated PCI-e lanes from the PCH, Middle slot shares lanes with two sata ports and disables said sata ports once a drive is installed, and the bottom slot shares with the bottom most PCI-e card slot.