What is new about the M.2 slot on the ASUS PN65 compared to the PN50 and PN51?

The ASUS PN65 bumps its M.2 slot to PCIe Gen 4, doubling the bandwidth ceiling over the PN50 and PN51. The 2.5-inch SATA III bay stays for backward compatibility. It’s the same dual-drive formula, just with a faster pipe to the NVMe drive.