Side-by-side: WD_BLACK SN8100 4TB ($700) vs WD_BLACK SN7100 4TB ($570). $/TB winner, specs, real-world picks for July 2026.
This is a generational matchup at 4 TB: the older-gen drive offers proven reliability and better $/TB, while the newer-gen sibling brings raw bandwidth that most users never tap.
Hardware-wise, the WD_BLACK SN8100 4TB runs on an SMI SM2508 controller that drew industry attention in 2024 for finally taming Gen 5 thermals. The WD_BLACK SN7100 4TB pairs an A101 controller that replaced the older WD designs in the SN7100 generation.
Prices favor the WD_BLACK SN7100 4TB by $32.50/TB ($142.50/TB versus $175.00/TB). Not a huge gap, but enough to be the tiebreaker if performance is similar.
In the read department, the WD_BLACK SN8100 4TB leads by roughly 7 GB/s. The difference is more academic than practical for typical use, but it does matter for video editors moving multi-GB project files.
Write performance separates them too. The WD_BLACK SN8100 4TB sustains 11,000 MB/s writes versus 6,700 MB/s for the WD_BLACK SN7100 4TB — a real advantage for video editors and anyone doing heavy file operations.
The DRAM-vs-HMB question divides opinion: WD_BLACK SN8100 4TB's on-board DRAM theoretically helps under sustained workloads, while WD_BLACK SN7100 4TB's HMB approach has matured enough that most users won't see the difference. Pick on price if everything else is similar.
If this purchase is for a PS5 storage expansion, the comparison flattens — Sony's PCIe Gen 4 controller normalizes both WD_BLACK SN8100 4TB and WD_BLACK SN7100 4TB to roughly equal in-game load times. The cheaper drive is the smart pick. Comparing across generations always invites the same question: does the bandwidth gap convert into user-visible improvements? Honest answer for the WD_BLACK SN8100 4TB vs WD_BLACK SN7100 4TB pairing: only for sustained sequential reads of multi-GB files. For content creators routinely rendering 4K or 8K video, the WD_BLACK SN8100 4TB's 11,000 MB/s sustained write is the deciding factor — multi-GB project files land noticeably faster than on the alternative. Note for handheld gamers: M.2 2280 is the desktop/laptop standard. Steam Deck and the ROG Ally line need 2230 drives — neither WD_BLACK SN8100 4TB nor WD_BLACK SN7100 4TB fits without modification.
Market context: the WD_BLACK SN8100 4TB ranks #3 of 6 Gen 5 4 TB drives we track by $/TB, while the WD_BLACK SN7100 4TB ranks #5 of 6 Gen 4 4 TB drives. Neither cracks the top of the value table, so it's worth glancing at the alternatives below before picking either.
As of July 27, 2026, these tracked drives undercut both the WD_BLACK SN8100 4TB and WD_BLACK SN7100 4TB on $/TB:
Go with the WD_BLACK SN8100 4TB for meaningfully faster reads (14,900 MB/s), higher sustained writes (11,000 MB/s), and a dedicated DRAM cache chip.
Go with the WD_BLACK SN7100 4TB for the lower retail price ($570 vs $700), and better $/TB economics ($142.50/TB).