Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Lexar - NM800 Pro 2TB | WD - Black SN850X 2TB |
|---|---|---|
| Endurance (TBW) | 1500 | 1200 |
| Sequential read | 7500 MB/s | 7300 MB/s |
| Sequential write | 6500 MB/s | 6600 MB/s |
Between the NM800 Pro 2TB and Black SN850X 2TB, the NM800 Pro 2TB comes out ahead in endurance (tbw) / sequential read, while the Black SN850X 2TB wins on sequential write. Overall, the NM800 Pro 2TB scores 68.8 and the Black SN850X 2TB scores 68.7 on our Mars Score.
Which should you buy?
These two are nearly even on the Mars Score (68.8 vs 68.7). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.
Pick the NM800 Pro 2TB if you care most about endurance (tbw) / sequential read. The biggest gaps in its favor are endurance (tbw), sequential read. The single most decisive one: Endurance (TBW) — 25.00% more. 1500 vs 1200.
Pick the Black SN850X 2TB if you care most about sequential write. Its strongest claims are sequential write. The single most decisive one: Sequential write — 1.54% more. 6600 MB/s vs 6500 MB/s.
Both ship with comparable capacity, interface, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: Lexar - NM800 Pro 2TB or WD - Black SN850X 2TB?
Lexar - NM800 Pro 2TB leads the current Mars Score by 0.1 points.The more useful decision is the trade-off behind that result: compare sequential read, sequential write against the way you will actually use the product.
Choose Lexar - NM800 Pro 2TB if…
Lexar - NM800 Pro 2TB has the measurable edge on tbw, read mbps.
Choose WD - Black SN850X 2TB if…
WD - Black SN850X 2TB has the measurable edge on write mbps.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Lexar - NM800 Pro 2TB wins
- ▲Endurance (TBW) — 25.00% more. 1500 vs 1200.
- ▲Sequential read — 2.74% more. 7500 MB/s vs 7300 MB/s.
Why WD - Black SN850X 2TB wins
- ▲Sequential write — 1.54% more. 6600 MB/s vs 6500 MB/s.
Spec comparison
Capacity
| Spec | Lexar - NM800 Pro 2TB | WD - Black SN850X 2TB |
|---|---|---|
| Capacity | 2000 GB | 2000 GB |
Performance
| Spec | Lexar - NM800 Pro 2TB | WD - Black SN850X 2TB |
|---|---|---|
| Sequential read | 7500 MB/slead | 7300 MB/s |
| Sequential write | 6500 MB/s | 6600 MB/slead |
| Interface | PCIe 4.0 x4 | PCIe 4.0 x4 |
| Form factor | M.2 2280 | M.2 2280 |
Endurance
| Spec | Lexar - NM800 Pro 2TB | WD - Black SN850X 2TB |
|---|---|---|
| Endurance (TBW)ⓘ | 1500lead | 1200 |
| Warranty | 5 yrs | 5 yrs |