Western Digital WD Black SN7100 1TB VS Western Digital WD Blue SN5100 1TB

Both drives deliver flagship-class read performance, but there is a small gap at the sequential level. The WD Black SN7100 reaches 7250 MB/s sequential read, edging out the WD Blue SN5100 at 7100 MB/s. In practice, that 150 MB/s difference is unlikely to be perceptible in everyday workloads such as booting an OS or launching applications, but it can matter when continuously transferring very large files — think multi-gigabyte video projects or disk images.

Where the two drives are completely indistinguishable is random read performance: both are rated at 1,000,000 IOPS. Random I/O is what actually governs responsiveness for typical desktop and gaming use — loading game assets, opening files, or running a database. Matching at this ceiling means users should expect identical ″snappiness″ in day-to-day tasks regardless of which drive they choose.

Overall, the SN7100 holds a narrow sequential read edge, making it the marginally stronger pick for throughput-intensive workflows. For mainstream use, however, the identical random read rating means both drives perform on equal footing where it counts most.

Write performance is where the gap between these two drives becomes more pronounced. The SN7100 posts 6900 MB/s sequential write against the SN5100's 6700 MB/s — a 200 MB/s spread that, while still modest in isolation, is slightly wider than what was seen on the read side. For creators regularly writing large media files or performing full-drive backups, this advantage can translate to a few seconds saved per operation at scale.

The more meaningful differentiator here is random write IOPS. The SN7100 is rated at 1,400,000 IOPS versus the SN5100's 1,300,000 IOPS — a 100,000 IOPS advantage, roughly 7.7% higher. Random write speed governs how quickly a drive handles fragmented, small-block operations such as installing software, compiling code, or running virtual machines. That headroom gives the SN7100 a tangible edge in write-intensive professional workloads.

Taken together, the SN7100 leads on both write metrics, and the advantage is more consistent than on the read side. For users whose workflows lean heavily on sustained writes or high-concurrency storage tasks, the SN7100 is the clearer choice. Casual users will find the SN5100 still delivers very strong write throughput for its class.

Underneath the shared M.2 PCIe 4.0 form factor, the most consequential difference is NAND flash type. The SN7100 uses TLC (Triple-Level Cell) storage, while the SN5100 uses QLC (Quad-Level Cell). TLC stores three bits per cell and QLC stores four, meaning QLC achieves higher density but at the cost of lower write endurance and typically reduced sustained write performance outside of cache bursts. For users who write to their drive heavily and frequently — video editors, developers, power users — TLC is the more resilient choice long-term.

Interestingly, both drives share an identical 600 TBW (Terabytes Written) rating and a 5-year warranty, which partially narrows the practical endurance gap on paper. One area where the SN5100 pulls ahead is its NVMe 2.0 compliance versus the SN7100's NVMe 1.4 — the newer spec introduces efficiency improvements and better queue management, though for mainstream consumer workloads the real-world difference is rarely significant today.

On balance, the SN7100 holds a structural advantage thanks to its TLC NAND, which tends to be more durable and consistent under sustained write pressure. The SN5100's QLC flash and newer NVMe version make it competitive on paper, but users prioritizing long-term reliability and write consistency should lean toward the SN7100.