Compare Samsung 990 EVO Plus 4TB and WD_BLACK SN850X 4TB: prices, speeds, $/TB. Which to buy in May 2026? Full spec breakdown.
Samsung 990 EVO Plus 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 990 EVO Plus 4TB runs on Samsung's Piccolo controller — DRAM-less with PCIe 4.0/5.0 dual-mode support. The WD_BLACK SN850X 4TB pairs the proprietary WD G2 silicon, optimized for the WD_BLACK line.
There's a modest pricing advantage for the WD_BLACK SN850X 4TB: $89.75/TB compared with $104.75/TB. For typical gaming and productivity, this becomes the deciding factor when specs are close.
The WD_BLACK SN850X 4TB carries a dedicated DRAM chip for FTL (Flash Translation Layer) mapping; the Samsung 990 EVO Plus 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 (7,250 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. 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.
The 990 EVO Plus uniquely supports both PCIe 4.0 x4 and PCIe 5.0 x2 modes — useful flexibility if you might upgrade motherboard generations.
Pick the WD_BLACK SN850X 4TB if you value the lower retail price ($359 vs $419), better $/TB economics ($89.75/TB), and a dedicated DRAM cache chip. WD_BLACK's SN850X earned its reputation through consistent sustained performance under gaming workloads — fewer micro-stutters during open-world streaming than budget alternatives.