Compare Samsung 9100 PRO 4TB and WD_BLACK SN850X 4TB: prices, speeds, $/TB. Which to buy in May 2026? Full spec breakdown.
Samsung 9100 PRO 4TB vs WD_BLACK SN850X 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 Samsung 9100 PRO 4TB runs on Samsung's in-house Presto controller, designed specifically for the 9100 PRO series. The WD_BLACK SN850X 4TB pairs the proprietary WD G2 silicon, optimized for the WD_BLACK line.
Price separates these two meaningfully. The WD_BLACK SN850X 4TB costs $89.75/TB versus $192.25/TB for the Samsung 9100 PRO 4TB — a 53% premium that needs justification in real benchmarks, not just spec-sheet bragging.
Read speeds favor the Samsung 9100 PRO 4TB: 14,800 MB/s versus 7,300 MB/s for the WD_BLACK SN850X 4TB, a 51% advantage. Sequential-heavy workloads notice; transactional workloads don't.
The Samsung 9100 PRO 4TB writes about 51% faster (13,400 MB/s vs 6,600 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.
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. 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 WD_BLACK SN850X 4TB is the better default unless you have a specific workload that needs the extra lanes. Heavy write workloads — video editing, RAW photo libraries, backup operations — favor the Samsung 9100 PRO 4TB's 13,400 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.
Pick the Samsung 9100 PRO 4TB if you value meaningfully faster reads (14,800 MB/s), and higher sustained writes (13,400 MB/s). 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 $769), 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.