Lexar NM620 256GB NVMe SSD Review
The Lexar NM620 256GB is a budget DRAM-less NVMe drive that trades write speed for affordability, making it a straightforward boot-drive upgrade from SATA.
Inside the NM620 256GB is the Lexar DM620 controller — a rebranded third-party chip — paired with Micron 96-layer 3D TLC NAND in an M.2 2280 single-sided layout. The drive is DRAM-less, relying on the host system's memory through the HMB (Host Memory Buffer) protocol to maintain mapping tables. It speaks NVMe 1.4 over a PCIe 3.0 x4 link.
The 256GB variant is the slowest in the NM620 family. Where the 512GB model reaches 2,400 MB/s writes and the 1TB hits 3,000 MB/s, this 256GB capacity drops to just 1,300 MB/s sequential writes. Reads stay at 3,000 MB/s, which is respectable for the capacity. The endurance rating of 125 TBW is on the low side even for a 256GB TLC drive — roughly 68 GB of writes per day over five years.
Direct rivals include the WD Blue SN550 250GB, Crucial P2 250GB, and Samsung 980 250GB. All four compete in the same entry-level NVMe bracket, though the Samsung 980 tends to pull ahead in real-world trace benchmarks. The NM620 undercuts on price and offers a five-year warranty, which is one year longer than the Samsung.
✅ Storage Comparisons:
🚀 Performance and benchmarks
The Lexar NM620 256GB is rated for up to 3,000 MB/s sequential reads and 1,300 MB/s sequential writes. Random performance comes in at up to 300,000 read IOPS and 256,000 write IOPS. Those sequential write numbers are roughly half of what the 1TB variant achieves — a direct consequence of fewer NAND dies sharing the write workload.
Lexar NM620 256 GB vs M.2 3.0 x 4 peers
Switch between sequential throughput and random IOPS to see how this drive stacks up against other M.2 3.0 x 4 SSDs in our database. The highlighted bar is the drive on this page — click any other bar to open that drive.
- ADATA SX 8800 Pro 512 GB: 3,500 MB/s read, 2,700 MB/s write
- ADATA SX 8800 Pro 1 TB: 3,500 MB/s read, 2,700 MB/s write
- ADATA XPG Spectrix S40G RGB 256 GB: 3,500 MB/s read, 3,000 MB/s write
- ADATA XPG Spectrix S40G RGB 512 GB: 3,500 MB/s read, 3,000 MB/s write
- Lexar NM620 256 GB (this drive): 3,000 MB/s read, 1,300 MB/s write
In practice, independent reviewers find the NM620 family delivers synthetic scores close to rated reads but falls short on sustained writes. The SLC cache on the 256GB model is relatively small; once it exhausts, write speeds settle to native TLC levels that can dip below 500 MB/s during large file transfers. For a boot drive handling mostly random reads and small writes, this limitation rarely surfaces. For anyone moving large video files or game libraries regularly, the 512GB or 1TB model is the better pick.
🖥️ Endurance and warranty
Lexar rates the NM620 256GB at 125 TBW (Terabytes Written) over a five-year warranty period. That works out to approximately 68 GB of writes per day, every day, for five years — a figure that comfortably exceeds the typical desktop workload of 20 to 40 GB per day. The drive carries a 1.5 million hour MTBF rating, though this is a population-level statistical measure rather than a guarantee for any individual unit. The warranty is limited by whichever comes first: the five-year term or exceeding the TBW allowance.
📊 Specs
| Category | Value |
|---|---|
| Capacity [?] | 256 GB |
| Interface [?] | M.2 3.0 x 4 |
| Controller [?] | Lexar DM620 |
| Memory type [?] | 3D TLC |
| DRAM [?] | n/a |
| Read speed (MB/s) [?] | 3000 |
| Write speed (MB/s) [?] | 1300 |
| Read IOPS [?] | 300000 |
| Write IOPS [?] | 256000 |
| Endurance (TBW) [?] | 125 |
| MTBF (million hours) [?] | 1.5 |
| Warranty (years) [?] | 5 |
Conclusion
The Lexar NM620 256GB is best suited as a low-cost boot or OS drive where the 1,300 MB/s write ceiling and 125 TBW endurance are unlikely to matter. Content creators and gamers who regularly move large files should step up to the 512GB or 1TB variant for the substantially faster writes. Those wanting stronger real-world performance at a similar price point should consider the Samsung 980 250GB, which trades a shorter warranty for better trace-based benchmark results. The NM620 256GB is a capable SATA replacement, nothing more and nothing less.
+ Pros
- 3,000 MB/s sequential reads on PCIe 3.0
- Five-year warranty
- Single-sided M.2 2280 fits slim laptops
- DRAM-less HMB keeps cost down
- NVMe 1.4 support
- Cons
- 1,300 MB/s writes — less than half the 1TB model
- 125 TBW endurance is low for TLC
- No included heatsink or software toolbox
- Small SLC cache fills quickly on large transfers
🛒 Buy this or similar SSD Storage:
✨ Video Review
Great Drive, Bad Competition - Lexar NM610 NVMe SSD Review
