Writes are indirect
NAND is written in pages and erased in larger blocks, so the controller remaps data rather than overwriting every bit in place.
STORAGE ATLAS
M.2 NVMe Solid-State Drive
An NVMe SSD is a compact computer of its own: NAND stores bits while a controller and firmware manage mapping, errors, wear, and host commands.
Representative form: single-sided M.2 2280 NVMe SSD. Package count and cache design vary.
Parallel flash channels
Controllers combine access across NAND dies and channels to raise throughput and hide individual flash latency.
Heat changes behavior
Sustained transfers can heat a compact M.2 drive enough for firmware to reduce performance and remain within safe limits.