Which is better, WD_BLACK SN850X 4TB or Lexar NM790 4TB? July 2026 side-by-side with prices, specs, and verdict.
A like-for-like comparison: both drives target the same buyer segment at the same Gen 4 4 TB class. The interesting question becomes which manufacturer's implementation aged better.
Hardware-wise, the WD_BLACK SN850X 4TB runs on WD's second-generation G2 in-house controller, tuned for sustained gaming I/O. The Lexar NM790 4TB pairs MaxioTech's MAP1602 silicon, the default choice for budget Gen 4 drives in 2024-2026.
WD_BLACK SN850X 4TB bundles a DRAM cache chip; Lexar NM790 4TB is DRAM-less. This sounds like a big deal but reviewers have been arguing for years about whether it actually matters in consumer use. For most workloads, no.
For PS5 expansion, both are PCIe Gen 4 M.2 2280 drives that meet Sony's minimum spec (7,300 MB/s read). The console can't take advantage of speeds beyond that, so save money by choosing the Lexar NM790 4TB. 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.
How do these two fit the wider Gen 4 4 TB field? Out of 6 tracked drives, the WD_BLACK SN850X 4TB is #4 on $/TB and the Lexar NM790 4TB is #1. That puts at least one of them near the top of the value table — a reasonable head-to-head to be choosing from.
At $127.50/TB, the Lexar NM790 4TB is already among the cheapest 4 TB drives we track — nothing in this class undercuts it. See the full $/TB ranking.
Lean toward the WD_BLACK SN850X 4TB when a dedicated DRAM cache chip top your priority list. The SN850X has been the best-selling Gen 4 NVMe in PCPartPicker builds for two consecutive years — Game Mode 2.0 prioritizes I/O when supported titles need it.
Lean toward the Lexar NM790 4TB when the lower retail price ($510 vs $535), and better $/TB economics ($127.50/TB) top your priority list. Budget-tier drives like the Lexar NM790 4TB have closed the gap with premium NVMes — the MAP1602 controller is genuinely competitive for everyday workloads at half the price.