Compare Crucial T705 4TB and WD_BLACK SN850X 4TB: prices, speeds, $/TB. Which to buy in July 2026? Full spec breakdown.
Crucial T705 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 Crucial T705 4TB runs on the Phison E26 — the first widely-deployed Gen 5 controller, capable but thermally demanding. 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: $133.75/TB compared with $153.25/TB. For typical gaming and productivity, this becomes the deciding factor when specs are close.
Read speeds favor the Crucial T705 4TB: 14,500 MB/s versus 7,300 MB/s for the WD_BLACK SN850X 4TB, a 50% advantage. Sequential-heavy workloads notice; transactional workloads don't.
The Crucial T705 4TB writes about 48% faster (12,700 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.
Heading to a PlayStation 5? Both drives drop into the console's M.2 bay and report identical real-world benchmarks since the PS5 caps storage at PCIe 4.0 speeds. The WD_BLACK SN850X 4TB wins this matchup on $/TB. 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 Crucial T705 4TB's 12,700 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.
Market context: the Crucial T705 4TB ranks #2 of 6 Gen 5 4 TB drives we track by $/TB, while the WD_BLACK SN850X 4TB ranks #4 of 6 Gen 4 4 TB drives. That puts at least one of them near the top of the value table — a reasonable head-to-head to be choosing from.
As of July 27, 2026, these tracked drives undercut both the Crucial T705 4TB and WD_BLACK SN850X 4TB on $/TB:
Pick the Crucial T705 4TB if you value meaningfully faster reads (14,500 MB/s), and higher sustained writes (12,700 MB/s). Crucial drives benefit from being a direct Micron product — the same NAND that powers competitors' drives, but at lower margins.
Pick the WD_BLACK SN850X 4TB if you value the lower retail price ($535 vs $613), and better $/TB economics ($133.75/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.