Lexar NM790 4TB Review — 4 TB of DRAM-less PCIe 4.0 Speed (2026)
Quick answer
Buy the Lexar NM790 4TB when the point of the drive is room: a full game library, a PS5 that no longer juggles installs, or a video archive that needs Gen4 speed without flagship trade-offs.
Read: 7400 MB/s Write: 6500 MB/s Endurance: 3000 TBW Warranty: 5 years Interface: M.2 4.0 x 4
The Lexar NM790 4TB combines 7,400 MB/s reads, 6,500 MB/s writes, and 3,000 TBW endurance on a single-sided PCIe 4.0 board that slots straight into a PS5.
Controller & Memory
The Lexar NM790 4TB keeps the recipe that made the smaller capacities popular: Maxio's 12nm MAP1602 controller, YMTC 232-layer TLC NAND, and no DRAM — Host Memory Buffer 3.0 and a dynamic SLC cache do the housekeeping instead. What makes the 4TB board notable is its layout: ServeTheHome's teardown found components on one side only, with nothing but a label on the reverse, which is rare at this capacity and keeps the drive compatible with console bays and laptop slots designed around single-sided sticks. AES-256 hardware encryption and TCG Opal 2.0 carry over, as do the 2.45 mm-thin 2280 dimensions.
Within the lineup, the 4TB model is the endurance and protocol leader. Lexar rates it at 3,000 TBW — double the 2 TB model's 1,500 TBW — and it ships with NVMe 2.0 support where the 512 GB through 2 TB capacities use NVMe 1.4. Speed ratings match the rest of the range at 7,400/6,500 MB/s, and ServeTheHome's review calls that essentially the ceiling of what PCIe 4.0 can deliver, give or take a hundred MB/s. Only the newer 8 TB model sits above it in capacity, and that one trades down to 7,000/6,200 MB/s.
For buyers, the 4TB NM790 lands in game-library and archive territory: at this size the math stops being about a handful of AAA installs and starts being about whole libraries, PS5 expansion, and multi-camera video projects. Against the WD Black SN850X 4TB, the NM790 gives up DRAM and a sliver of rated write speed, but counters with a single-sided board and a higher 3,000 TBW endurance rating to the SN850X's 2,400 TBW. The Crucial T500 plays the same DRAM-less game with stronger sustained writes, while the Samsung 990 Pro remains the pick if DRAM and peak consistency matter more than raw capacity.
Storage Comparisons:
NM790 Performance & Benchmarks
Lexar rates the 4TB NM790 at 7,400 MB/s sequential reads and 6,500 MB/s writes over PCIe 4.0 x4, with random performance rated up to 900K IOPS in both directions. Those are manufacturer figures, but credible ones: ServeTheHome tested the 4TB as a boot drive on a Ryzen 9 7900X platform and judged its rated speeds essentially as fast as a Gen4 drive can get, give or take 100 MB/s. In practice that means DirectStorage titles and PS5 games load well past Sony's 5,500 MB/s recommendation, and 4K video imports or library-wide file moves finish in seconds rather than minutes.
Lexar NM790 4 TB vs M.2 4.0 x 4 peers
Switch between sequential throughput and random IOPS to see how this drive stacks up against other M.2 4.0 x 4 SSDs in our database. The highlighted bar is the drive on this page — click any other bar to open that drive.
- Patriot Viper PV593 1 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV593 2 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV593 4 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV573 2 TB: 14,000 MB/s read, 12,000 MB/s write
- Lexar NM790 4 TB (this drive): 7,400 MB/s read, 6,500 MB/s write
The sustained picture carries the usual DRAM-less caveats. Writes ride a dynamic SLC cache, and once it fills during a very large transfer, throughput drops back to native TLC rates for the remainder — a non-event for game installs and boot duty, but visible when hundreds of gigabytes move in one session. Thermals also deserve attention at 4 TB, because the NAND population is denser on the same single-sided layout; testing across the NM790 line has documented thermal throttling during extended SNIA stress writes, so a motherboard heatsink or the bundled-heatsink variant is the smart setup. Within those limits, reviewers consistently find the drive indistinguishable from pricier Gen4 competitors in everyday use.
Lexar NM790 vs Competitors
See how the NM790 stacks up against other M.2 4.0 x 4 drives in our database:
Compare with rival drives:
Endurance, TBW & Warranty
Lexar covers the NM790 4TB with a 5-year limited warranty rated to 3,000 TBW, whichever limit comes first. That endurance budget works out to roughly 600 TBW per terabyte — ServeTheHome's benchmark for a healthy modern TLC drive — and at a demanding 40 GB of writes per day it would take more than two centuries to exhaust. The rated MTBF is 1.5 million hours, a fleet-level statistic rather than a promise for any individual drive. Sudden power-loss protection, wear leveling, and bad-block management run in firmware, and hardware AES-256 encryption is built in. The same 5-year terms apply line-wide, with 1,500 TBW at 2 TB and 1,000 TBW at 1 TB; claims are handled through Lexar directly in most regions.
Lexar NM790 4 TB Specifications
| Category | Value |
|---|---|
| Capacity [?] | 4 TB |
| Interface [?] | M.2 4.0 x 4 |
| Controller [?] | Maxiotech MAP1602A |
| Memory type [?] | YMTC 232-L TLC |
| DRAM [?] | No |
| Read speed (MB/s) [?] | 7400 |
| Write speed (MB/s) [?] | 6500 |
| Read IOPS [?] | 900000 |
| Write IOPS [?] | 900000 |
| Endurance (TBW) [?] | 3000 |
| MTBF (million hours) [?] | 1500000 |
| Warranty (years) [?] | 5 |
Verdict: Is the NM790 Worth It in 2026?
Buy the Lexar NM790 4TB when the point of the drive is room: a full game library, a PS5 that no longer juggles installs, or a video archive that needs Gen4 speed without flagship trade-offs. Skip it if your days are filled with sustained multi-hundred-gigabyte writes — the WD Black SN850X 4TB, with its 2 GB of DRAM and stronger random performance, is the calmer tool for scratch-disk duty. Within Lexar's own range, the 4TB is the sweet spot: the 8 TB model adds room but gives up rated speed, while the 2 TB halves the endurance budget. For PCIe 4.0 bulk storage in 2026, this is one of the most complete packages on the market.
+ Pros
- 7,400 MB/s reads and 6,500 MB/s writes
- 3,000 TBW endurance with a 5-year warranty
- Single-sided PCB even at 4 TB capacity
- NVMe 2.0 protocol support
- AES-256 encryption with TCG Opal 2.0
- Rated up to 900K random-read and write IOPS
- Cons
- No DRAM cache on the PCB
- No heatsink included on the base model
- SLC cache exhaustion slows very large transfers
- Thermal throttling without added cooling under sustained load
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