The Lexar NM790 2TB is the DRAM-less Gen4 drive to beat: published tests put it near the top of its class for game loads and copies, its TLC NAND carries a 1,500 TBW rating, and it draws less power than DRAM-equipped rivals. Sustained-write slowdowns and missing PS5 HMB support are real caveats, but they bite only in edge cases.
— THE VERDICT · JUDGEANY EDITORSWhat the NM790 is
The Lexar NM790 is a PCIe Gen4 x4 NVMe SSD in the standard M.2 2280 form factor, and the 2TB version covered here — model LNM790X002T-RNNNU — is the bare drive without a factory heatsink. Lexar rates the 1TB, 2TB and 4TB models at up to 7,400 MB/s sequential reads and 6,500 MB/s writes, with random reads up to 1,000,000 IOPS on the 512GB to 2TB models. The 512GB model is slower, at 7,200 MB/s reads and 4,400 MB/s writes, and the later 8TB model is rated at 7,000 MB/s reads and 6,200 MB/s writes, so the headline figures belong to the mainstream capacities, not the whole family. Under the sticker sits a Maxio MAP1602 controller paired with 232-layer TLC NAND, and there is no DRAM chip on board: mapping data is handled through Host Memory Buffer (HMB) 3.0, which borrows a slice of system memory, plus a dynamic SLC cache.
What published tests found
Tom's Hardware called the NM790 the fastest DRAM-less Gen4 SSD in its testing and praised its real-world performance and sustained write behaviour. LanOC's 2TB testing landed close to the headline numbers in CrystalDiskMark 8, with 7,188 MB/s reads and 6,636 MB/s writes — the write figure passing the rated 6,500 MB/s — and its AS SSD copy benchmark put the drive ahead of every other Gen4 drive it tested, behind only a PCIe 5.0 model. PC Gamer's 4TB testing came out almost identical to the rated figures, at 7,106 MB/s reads and 6,504 MB/s writes. TechPowerUp, testing the 4TB model, found the thin factory heat-spreader foil sufficient for everything except the worst-case scenarios. We don't run a lab; these are published findings, and the scores below are editorial judgments based on them.
The conflict: sustained writes, PS5, and the missing DRAM
The less clean half of the story matters, so it gets its own section. PC Gamer found that after roughly 642GB of continuous writing on the 4TB model — about 16% of its capacity — the SLC cache ran out and write speed fell to around 2,500 MB/s on native TLC, and Guru3D reached a similar conclusion, noting that write speeds degrade under sustained heavy workloads. LanOC found a soft spot too: the NM790's 4K write IOPS sat below most of its comparison drives, even while its copy tests led the Gen4 field. On PlayStation 5, TechRadar's heatsink-version testing scored well in the console's internal benchmark but warned that the PS5 does not support HMB, and that the drive can stutter in the most demanding games. None of this overturns the main conclusion. The workloads that expose it — a single uninterrupted multi-hundred-gigabyte write, or the most demanding PS5 titles — are not what most buyers do day to day. Game loads, app launches and ordinary file copies are bursty, and that is where the published results consistently put the NM790 near the top of the Gen4 class. Buyers who regularly move hundreds of gigabytes in one go, or who want a PS5 drive with no caveats at all, should weigh that honestly.
Efficiency, endurance, and fit
Lexar claims up to 40% lower power consumption than DRAM-equipped Gen4 drives, based on its own internal testing, and the DRAM-less design is part of why the drive runs cool enough for laptops: PC Gamer measured just 57°C while copying a 30GB test folder, rising to 72°C during a continuous transfer of more than 200GB, both without active cooling. The 2TB model carries a 1,500 TBW endurance rating, with a 1,500,000-hour MTBF and a five-year limited warranty behind it. At 80 x 22 x 2.45mm and 6 grams, single-sided, it fits laptops and tight slots that reject double-sided drives, and LanOC notes that Lexar includes a small M.2 mounting screw in the box. The bare 2TB drive covered here has only a thin heat spreader, so a motherboard heatsink or decent airflow is worth having for long writes, and PS5 owners should choose the heatsink version or fit a console-compliant heatsink rather than installing the bare drive.
What reviewers keep coming back to
The recurring theme across published reviews is value without an obvious catch for everyday use: near-ceiling Gen4 speeds, TLC rather than QLC NAND, and a 1,500 TBW endurance rating on the 2TB model, all from a drive that usually sits below the flagship tier. Check the current price on Amazon before buying, since SSD pricing moves often and the NM790's case rests on staying cheaper than DRAM-equipped alternatives. The recurring complaints mirror the reviewers' caveats: no DRAM, no bundled heatsink on this version, and write speeds that step down once the SLC cache is exhausted.
Who should buy it
Gamers and creators on a Gen4 PC who want 2TB of fast TLC storage, laptop owners who value low power draw, and anyone upgrading from PCIe Gen3 or SATA should look at the 2TB NM790 — check the current price on Amazon. Skip it if you routinely write hundreds of gigabytes in a single session, if you want a no-compromise PS5 drive, or if you are building on a Gen5 platform where the ceiling has moved on.