WD_BLACK SN8100 2TB ($459) vs Lexar NM790 2TB ($149). $/TB analysis, performance, and use-case recommendations.
When generations cross paths in a comparison like this one, the older-spec drive almost always wins on value while the newer one wins on benchmarks. Whether that benchmark advantage matters depends entirely on what you do with the drive.
Hardware-wise, the WD_BLACK SN8100 2TB runs on the SMI SM2508 — a 6nm Gen 5 controller running notably cooler than first-gen Phison E26 designs. The Lexar NM790 2TB pairs MaxioTech's MAP1602 silicon, the default choice for budget Gen 4 drives in 2024-2026.
The cost difference is hard to ignore: 68% per TB (Lexar NM790 2TB at $74.50/TB versus WD_BLACK SN8100 2TB at $229.50/TB). Unless you specifically need the WD_BLACK SN8100 2TB's peak performance, the Lexar NM790 2TB delivers more storage for the money.
Read speeds favor the WD_BLACK SN8100 2TB: 14,900 MB/s versus 7,400 MB/s for the Lexar NM790 2TB, a 50% advantage. Sequential-heavy workloads notice; transactional workloads don't.
The WD_BLACK SN8100 2TB writes about 41% faster (11,000 MB/s vs 6,500 MB/s). Whether that matters depends entirely on what you write to the drive — gameplay capture and large project saves benefit, browsing and gaming do not.
Cache architecture differs: WD_BLACK SN8100 2TB has DRAM hardware, Lexar NM790 2TB uses HMB. For OS, gaming, browsing — indistinguishable. For databases, large file ops, or 4K video editing — DRAM has a small but consistent edge.
If this purchase is for a PS5 storage expansion, the comparison flattens — Sony's PCIe Gen 4 controller normalizes both WD_BLACK SN8100 2TB and Lexar NM790 2TB to roughly equal in-game load times. The cheaper drive is the smart pick. The Gen 5 WD_BLACK SN8100 2TB pulls ahead on sequential bandwidth, but Gen 5 advantages rarely surface during everyday tasks — most software hasn't been rewritten to exploit 14,000+ MB/s pipelines. Heavy write workloads — video editing, RAW photo libraries, backup operations — favor the WD_BLACK SN8100 2TB's 11,000 MB/s sustained write speed. Both drives use the 2280 form factor, which is too long for Steam Deck or ROG Ally — you'd need a 2230 variant if either manufacturer offers one, or a dedicated handheld-format drive instead.
The WD_BLACK SN8100 2TB is the right call if meaningfully faster reads (14,900 MB/s), higher sustained writes (11,000 MB/s), and a dedicated DRAM cache chip matter to you.
The Lexar NM790 2TB is the right call if the lower retail price ($149 vs $459), and better $/TB economics ($74.50/TB) matter to you. Budget-tier drives like the Lexar NM790 2TB have closed the gap with premium NVMes — the MAP1602 controller is genuinely competitive for everyday workloads at half the price.