The Synology DS1520+ has NVMe cache slots, but don't expect storage

Synology’s approach to NVMe on the DS1520+ is conservative: two M.2 slots accelerate your workloads via cache, but they won’t host a storage volume. The five drive bays accept any mix of 3.5-inch and 2.5-inch SATA drives. It’s fast, but those M.2 slots aren’t expandable storage.