Compare WD_BLACK SN8100 4TB and Lexar NM790 4TB: prices, speeds, $/TB. Which to buy in May 2026? Full spec breakdown.
WD_BLACK SN8100 4TB vs Lexar NM790 4TB pits two different generations against each other at 4 TB. The question isn't which is faster on paper — that's settled — it's whether the bandwidth gap shows up in your specific workload.
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 Lexar NM790 4TB pairs a MAP1602 controller built specifically for DRAM-less HMB designs.
Price separates these two meaningfully. The Lexar NM790 4TB costs $67.25/TB versus $207.25/TB for the WD_BLACK SN8100 4TB — a 68% premium that needs justification in real benchmarks, not just spec-sheet bragging.
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 6,500 MB/s for the Lexar NM790 4TB — a real advantage for video editors and anyone doing heavy file operations.
The WD_BLACK SN8100 4TB carries a dedicated DRAM chip for FTL (Flash Translation Layer) mapping; the Lexar NM790 4TB relies on HMB (Host Memory Buffer), borrowing 64 MB from system RAM. The practical gap shows up only under sustained random write loads.
For PS5 expansion, both are PCIe Gen 4 M.2 2280 drives that meet Sony's minimum spec (7,400 MB/s read). The console can't take advantage of speeds beyond that, so save money by choosing the Lexar NM790 4TB. The leap from Gen 4 to Gen 5 doubles peak throughput on paper but produces single-digit-percent improvements in game load times, OS boot, and most productivity benchmarks. The Lexar NM790 4TB is the better default unless you have a specific workload that needs the extra lanes. 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 Lexar NM790 4TB fits without modification.
Pick the WD_BLACK SN8100 4TB if you value meaningfully faster reads (14,900 MB/s), higher sustained writes (11,000 MB/s), and a dedicated DRAM cache chip.
Pick the Lexar NM790 4TB if you value the lower retail price ($269 vs $829), and better $/TB economics ($67.25/TB). The Lexar NM790 4TB captures the value tier well: same NAND class as flagships, paired with a DRAM-less controller that costs less and uses HMB for the address-mapping table.