Relative Value64balanced preset
Western Digital Black SN850X 4TB vs Samsung 990 Pro 4TB — value comparison
See current offers for Western Digital Black SN850X 4TB
Relative Value54balanced preset
Western Digital Black SN850X 4TB shows higher Relative Value under balanced weights at the current dataset offers: 64 vs 54. The result crosses over if Samsung 990 Pro 4TB reaches about $667 or below.
Price data · US · USD · New · A 2026-09-11 · B 2026-09-11Coverage · 10 tracked new-offer records across both modelsBenchmark confidence · no estimate flags on these two recordsAffiliate links · We may earn a commission from these links. Scores are calculated separately using our methodology.
02 · Decision matrix
One decision, three separate questions
Capability ignores price. Relative Value adds the current dataset offers and your priorities. Keeping them separate prevents a cheap product from being mistaken for the faster product.
The decision, split by questioncapability · value · price are separate answers
Capability by task
| Scenario | Western Digital Black SN850X 4TB | Samsung 990 Pro 4TB |
|---|---|---|
| System Drive | S#89 | S#46 |
| Game & File Storage | S#61 | S#41 |
| Heavy Creative Work | S#86 | S#51 |
They grade identically in all 3 graded scenarios — the tier table won't decide this one, so compare price and Value below. These are the same S–F grades as the tier list — capability only, price excluded. The value rows below add prices from the 2026-09-11 offer frame. How tiers are assigned →
Relative Value by priority
Balancedhigher relative value lit
64 ✓
54
System Drivepractically even (≤3 pts)
27
25
Game & File Storagehigher relative value lit
80 ✓
68
Heavy Creative Workpractically even (≤3 pts)
29
26
Strict Budgethigher relative value lit
40 ✓
31
Both products are normalized within the same in-stock market frame per preset. A check marks the higher Relative Value; a difference of 3 points or less is shown as practically even.
03 · Price crossover
The price changes the answer
Current offers, crossover points and Strong Value thresholds answer different questions. Thresholds are calculations, not price forecasts.
A · Western Digital Black SN850X 4TB
- Current dataset offer · NewUS · USD · snapshot 2026-09-11
- $650
- Beats Samsung 990 Pro 4TB atbalanced weights; rival offer held fixed
- $827
- Strong Value at80+ Relative Value threshold
- $474
B · Samsung 990 Pro 4TB
- Current dataset offer · NewUS · USD · snapshot 2026-09-11
- $849
- Beats Western Digital Black SN850X 4TB atbalanced weights; rival offer held fixed
- $667
- Strong Value at80+ Relative Value threshold
- $487
04 · Where to buy
Current offers for both products
Dated New-condition price snapshots for only the two products in this comparison. Confirm the final price and availability at the store.
A · Western Digital Black SN850X 4TB
New · US · USDAmazon Affiliate
Check on AmazonB · Samsung 990 Pro 4TB
New · US · USDAmazon Affiliate
Check on Amazon05 · Capability
Capability indexes, side by side
Price is intentionally excluded here so the more capable product and the better-value product cannot be confused.
Drive capability
7300
7450
7450
Sequential read (MB/s)
7300
7450
7450
Sequential write (MB/s)
6600
6900
6900
A · Western Digital Black SN850X 4TBB · Samsung 990 Pro 4TBEach row keeps the unit or category index named in its label; bar length compares A and B within that row.Western Digital Black SN850X 4TB shows higher Value under every weighting we test — a stable result in the 2026-09-11 offer frame.
06 · Platform & ownership
Fit, compatibility and ownership context
Only verified structured compatibility and ownership fields are shown. Check the exact system, board manual and vendor QVL before purchase; missing fields are never guessed.
A · Western Digital Black SN850X 4TB
- InterfaceM.2 PCIe 4.0 x4
- Form factorM.2-2280
- Capacity4,000 GB
- DRAM cache4GB DDR4
- Heatsink includedNo
- Write endurance2,400 TBW
- Warranty (typical new)60 mo
B · Samsung 990 Pro 4TB
- InterfaceM.2 PCIe 4.0 x4
- Form factorM.2-2280
- Capacity4,000 GB
- DRAM cache4GB
- Heatsink includedNo
- Write endurance2,400 TBW
- Warranty (typical new)60 mo
07 · Specifications
Key specifications
Directional checkmarks appear only on numeric fields where more or less has a clear meaning. They are not an overall verdict.
| Specification | Western Digital Black SN850X 4TB | Samsung 990 Pro 4TB |
|---|---|---|
| Interface | M.2 PCIe 4.0 x4 | M.2 PCIe 4.0 x4 |
| Form factor | M.2-2280 | M.2-2280 |
| Capacity | 4,000 GB | 4,000 GB |
| Sequential read | 7,300 MB/s | 7,450 MB/s✓ |
| Sequential write | 6,600 MB/s | 6,900 MB/s✓ |
| Write endurance | 2,400 TBW | 2,400 TBW |
| DRAM cache | 4GB DDR4 | 4GB |
| NAND type | SanDisk 112-layer TLC | Samsung TLC V-NAND |
| Controller | WD Proprietary | Samsung Pascal (8nm) |
| Heatsink included | No | No |
| Current dataset offer · New | $650snapshot 2026-09-11✓ | $849snapshot 2026-09-11 |
| Warranty (typical new) | 60 mo | 60 mo |
“Not tracked” means the source data does not contain a verified value; no default or guessed specification is substituted.
08 · Customize
Try other models and your own priorities
Presets are starting points. Swap either side, then open Advanced weights only if you want to tune the formula directly.
09 · Alternative
A third option worth checking
The same scenario and market frame checks whether another currently priced model offers a cleaner trade-off.
Worth considering instead
Crucial T710 1TB — same S-tier capability for System Drive, about $416 cheaper · Value 100.
Neither of the two above is the only answer — this one clears the same bar for less. ⇄ Compare all three
10 · Decision guide
Choose based on the trade-off you actually want
These are evidence-linked conditions, not universal buying verdicts. Feature ecosystems, software support and platform preferences remain your call.
Choose A · Western Digital Black SN850X 4TB if…
- Your priorities resemble Balanced, Game & File Storage, Strict Budget — it has higher Relative Value under those presets at the snapshot offers.
- You can find it at or below its Strong Value threshold of $474 under balanced weights.
Choose B · Samsung 990 Pro 4TB if…
- You can find it at or below its Strong Value threshold of $487 under balanced weights.
11 · Methodology & FAQ
Read the methodology →How to read this comparison
The formula is a linear weighted sum inside the current comparison frame. Capability, price and user priorities stay visible as separate inputs so the result can be challenged and changed.
- Which is better value right now: Western Digital Black SN850X 4TB or Samsung 990 Pro 4TB?
- Under the balanced preset and the 2026-09-11 offer frame, Western Digital Black SN850X 4TB has higher Relative Value under this configuration (64 vs 54). Value is price-dependent and moves with your weighting; capability is a separate question, answered by the tier table.
- Which one is more capable, ignoring price?
- They grade identically in all 3 graded scenarios — the tier table won't decide this one, so compare price and Value below.
- At what price does the Samsung 990 Pro 4TB become the better value?
- Holding the Western Digital Black SN850X 4TB offer dated in the 2026-09-11 frame fixed, the calculation flips in favour of the Samsung 990 Pro 4TB at roughly $667 or below (balanced preset). Not a price forecast.
- Where can I compare current offers for both?
- Dated offer snapshots for both models are listed on their product pages (linked above); the interactive calculator recalculates both with your own weights and budget.
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Offer frame: 2026-09-11 · dataset generated 2026-09-11 · formula ssd-value-v1.5-benefit-cost-product · Value Score is an estimate based on our current dataset, selected weights, market prices and methodology — not an official product rating or a price forecast. Target prices are calculation thresholds, not predictions. Methodology · Report a data error