Choosing between NVMe in external case vs -

PCIe vs PCIe SSDs Benchmarked m 2 slot vs nvme You should not be worrying too much about the M+B keying as what you need is an M2 PCIe NVMe SSD which will be any such SSD you can find m24 slot wallet NVME drive uses pci-e signal, while SATA still uses SATA signal They are quite different Most ssd enclosures only support either one

m2 pcie 40 in 30 slot 2 SSDs: SATA and NVMe SATA uses an older interface with one designed around hard drives while NVMe is designed for flash memory