Does HP Z420 compatible with SATA or NVMe ssd?

2 slots will support both SATA and NVMe SSDs Make sure to check what SSD technology your motherboard can support Advantages:

Figure 2 SATANVMe Module with 2 drives adapter with back-to-back adapter installed in a PCIe slot The module offered is

m24 slot wallet 2 SATA SSD drives mSATA hard drives were well established and many motherboards were not compatible with the latest expansion ports As form

m2 nvme slot The slot can interface with SATA , PCI Express (the default