OCPC M.2 NVMe is vastly faster than SATA 3, using the high-speed PCIe bus for multi-gigabyte speeds (e.g., 3,000-7,000MB/s), while SATA 3 (even in M.2 form) is limited to ~550MB/s by its older interface, making NVMe ideal for OS/large files, though M.2 is the form factor, supporting both slower SATA and faster NVMe protocols, so always check motherboard compatibility for NVMe performance.