SanDisk WD_BLACK SN7100 internal SSD 4 TB M.2 2280 NVMe PCIe 4.0, 7000 MB/s

Sequential reads of up to 7000 MB/s and writes of up to 6700 MB/s mean the operating system starts quickly, games load in a short time and video files tens of gigabytes in size copy in seconds rather than minutes. These are the manufacturer's maximum figures, reached in a PCIe 4.0 slot. Write speed is almost on par with read speed, which helps when saving large projects.

Everyday use is mostly small files: booting the system, opening programs, browser cache and game data. What counts here is random 4K performance, which the manufacturer rates at up to 900,000 IOPS for reads and up to 1,350,000 IOPS for writes. The higher this figure, the less waiting there is when several programs access the drive at the same time.

Four terabytes hold the operating system together with a large games library, a photo archive or video editing projects on a single drive. If your system and data used to live on separate drives, everything can now sit on one fast NVMe SSD. The large capacity also leaves room for updates and temporary files, which matters for keeping the drive fast.

The drive uses 3D TLC NAND, where each memory cell stores three bits and the cells are stacked in multiple layers. This gives high capacity on a compact board and is the most common balance of speed, capacity and endurance in consumer SSDs. Compared with QLC memory, TLC usually holds its speed better during long sustained writes.

The M.2 2280 form factor means a drive 22 mm wide and 80 mm long, the most common M.2 size on current desktop motherboards and in laptops. The drive weighs only about 6 grams and mounts directly on the board with no cables. Your computer needs a free M.2 slot that supports NVMe drives, and for full speed the slot has to be PCIe 4.0.

Gamers whose library no longer fits on a smaller drive; photographers and video editors who open large files and need fast saving; desktop builders who want one large system drive instead of several small ones; and laptop owners with an M.2 2280 NVMe slot who want to replace the old drive with a larger and faster one.