Should an industrial computer use an M.2 NVMe or SATA SSD? What happens if we fit the wrong type?

Speed: SATA III tops out around 550 MB/s; NVMe PCIe Gen3 x4 reaches about 3,500 MB/s, and Gen4 is faster still. NVMe only makes a difference with large continuous reads or writes, such as multi-camera video recording or loading images for an AI model. For HMIs and data collection, SATA is enough. Heat: fast NVMe drives run noticeably hotter and throttle when overheated. In a fanless machine in a hot cabinet, choose an NVMe drive with a heatsink or a machine with a thermal pad pressing on the drive. Wrong type: M.2 slots vary. An M-key slot may support NVMe, SATA or both; a B-key slot is usually SATA or intended for a 4G module. A drive that fits physically but uses the other protocol is simply not detected; it causes no damage. Length must also match, written as 2242, 2260 or 2280 (22 mm wide, 42–80 mm long). Always check the model's datasheet for the protocol and lengths each slot supports.