Compare Samsung 990 PRO 4TB and WD_BLACK SN850X 4TB: prices, speeds, $/TB. Which to buy in May 2026? Full spec breakdown.
Both the Samsung 990 PRO 4TB and WD_BLACK SN850X 4TB sit in the Gen 4 category at 4 TB, so the matchup turns on controller efficiency, cache topology, and current pricing rather than raw class differences.
Hardware-wise, the Samsung 990 PRO 4TB runs on Samsung's 8nm Pascal controller, the silicon powering the 990 PRO line. The WD_BLACK SN850X 4TB pairs the proprietary WD G2 silicon, optimized for the WD_BLACK line.
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 WD_BLACK SN850X 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.
Samsung's PRO line has the longest track record for firmware reliability — over a decade of consumer SSDs with global RMA support.
Pick the WD_BLACK SN850X 4TB if you value the lower retail price ($359 vs $389), and better $/TB economics ($89.75/TB). WD_BLACK's SN850X earned its reputation through consistent sustained performance under gaming workloads — fewer micro-stutters during open-world streaming than budget alternatives.