NVME M2 drives: which slot to use?

2 may completely replace all aging Serial ATA formats The slot can interface with SATA (the cable that may be connected to the storage

Yes that's the confusion! I read that manual and when I spoke to customer support, they said second slot is also Gen 4 Maybe they are

m2 slot types There are several connector types that SSDs use to interface with a computer, including SATA, PCIe, , , mSATA, SATA Express, and even none

m24 slot wallet 2 SATA SSDs have two slots in the interface connector, while PCIe SSDs have only one slot in the interface connector Non-Standard PCIe SSDs