Samsung 990 EVO Plus 4TB ($574) vs WD_BLACK SN850X 4TB ($659). $/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 Samsung 990 EVO Plus 4TB runs on the dual-mode Samsung Piccolo silicon that uniquely runs PCIe 5.0 x2 or PCIe 4.0 x4. The WD_BLACK SN850X 4TB pairs WD's G2 controller — manufactured by SanDisk and tuned for low-latency gaming workloads.
The cheaper drive — Samsung 990 EVO Plus 4TB at $143.50/TB — saves you $21.25 per TB versus the WD_BLACK SN850X 4TB. Worth it if you're capacity-constrained; either works if you just want one fast drive.
Cache architecture differs: WD_BLACK SN850X 4TB has DRAM hardware, Samsung 990 EVO Plus 4TB 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 Samsung 990 EVO Plus 4TB and WD_BLACK SN850X 4TB to roughly equal in-game load times. The cheaper drive is the smart pick. The Gen 5 Samsung 990 EVO Plus 4TB 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. Note for handheld gamers: M.2 2280 is the desktop/laptop standard. Steam Deck and the ROG Ally line need 2230 drives — neither Samsung 990 EVO Plus 4TB nor WD_BLACK SN850X 4TB fits without modification.
Market context: the Samsung 990 EVO Plus 4TB ranks #2 of 6 Gen 5 4 TB drives we track by $/TB, while the WD_BLACK SN850X 4TB ranks #5 of 6 Gen 4 4 TB drives. One of them is genuinely among the cheapest options in its class, so this matchup includes a real value pick.
As of September 7, 2026, these tracked drives undercut both the Samsung 990 EVO Plus 4TB and WD_BLACK SN850X 4TB on $/TB:
The Samsung 990 EVO Plus 4TB is the right call if the lower retail price ($574 vs $659), and better $/TB economics ($143.50/TB) matter to you. Among Samsung's lineup, the 990 EVO Plus is the only consumer drive that physically supports dual-generation PCIe — same hardware, different bus speed depending on platform.
The WD_BLACK SN850X 4TB is the right call if a dedicated DRAM cache chip matter to you. Among Gen 4 flagships, the SN850X strikes a sweet spot — premium silicon at sub-Samsung pricing, with WD's established RMA process to back it up.