The Lexar NM790 demonstrates just how far Gen 4 NVMe drives have come. It’s affordable, an excellent all-around performer, and boasts exceptional power conservation and good thermal control. All that’s missing is hardware encryption and a 4TB model.
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The world of NAND storage is standing on the edge of uncharted territories, with capacities and performance likely to grow significantly in the near future.
With Gen 5 drives taking the performance high ground but beyond the budget of many users, the market for Gen 4 drives is about to heat up. And if the new Lexar NM790 is anything to go by, for those in the NAND storage sector, prices are heading down, and the performance of even budget drives is going up.
This is all good news for the consumer, but is this the right time to invest in a PCIe Gen4 NVMe drive?
Design & build
No heatsink option
We’ve talked about NVMe drive design and how for the most part, the 2280 M.2 form factor has all but eliminated what small amounts of variation previously existed.
Therefore, it shouldn’t surprise anyone that the NM790 is a basic design with the NAND modules and controller on the upper surface, covered only by a thin sticker.
The underside has no visible components at all, hinting that the NM790 was designed to be as simple as possible to make and highly reliable.
Without a heatsink, this design will easily fit inside a laptop, PC, or PlayStation 5 – though if you want to use it in the console you’ll have to ignore Sony’s advice to stick to SSDs with a heatsink.
This is one drive where you might be willing to take that chance though: as we’ll talk about later, the power consumption of this drive is dramatically less than that of some other Gen 4 NVMe drives, and therefore it doesn’t generate the same amount of heat.
Specs & features
Caps at 2TB storage
No hardware encyrption
Lexar is producing only three sizes for the NM790, offering it in 512GB, 1TB, and 2TB models. The lack of a 4TB drive is a disappointment, and we hope Lexar adds this and maybe an 8TB drive in the future.
Getting the maximum performance from this drive requires an NVMe 2.0 M.2(2280) slot that supports PCIe Gen 4 x4 operations. It will work in a Gen 3 slot, but you won’t experience the performance levels seen in our testing.
Prior to this point, we’d recommend that those with a PCIe Gen 3 slots buy drives designed for that interface, but with products like the NM790, maybe that advice needs updating. Because a Gen 4 drive will still perform well, it has better potential should you upgrade your system, and the prices of Gen 3 drives aren’t substantially less.
What this drive has that’s generally better than older designs is that it supports HMB 3.0 and Dynamic SLC Caching, enabling it to achieve and sustain high levels of performance using the RAM of the host system and the ability to convert NAND to cache memory dynamically.
For those with plenty of RAM and lots of space free on the drive, it is possible to sustain write speeds for large files without exposing the underlying speed of the MLC NAND on the drives to the user. An added bonus for the drive maker is that this avoids using expensive DRAM to perform the caching, which also consumes additional power.
What Lexar isn’t discussing is the controller on this drive, but a few other indicators, like power use, hint that it might not be a Phison E18 or a derivative of that design, but something created in-house.
When we first encountered Gen 4 drives, the performance they offered was impressive, but power consumption and, by extension, heat generation were often an issue.
The NM790 shows how far module design has come in the past couple of years since it uses almost half the power of Lexar’s previous NM800PRO design with a 6W overhead, requiring only 3.5W.
To compare that power draw to other popular designs, the Samsung 990 Pro 2TB can demand up to 5.8W, the Kioxia Exceria Pro needs up to 8.9W, and the Kingston KC3000 2TB wants a worrying 9.9W.
While the amount of voltage in all these drives isn’t anything that users with a mains-connected desktop system would be concerned about, for those with a laptop, the NM790 might be a perfect choice. Or, it would be if it had one feature that Lexar chose to leave out.
From what we understand, this drive doesn’t support hardware encryption. While it is possible to use software to encrypt the contents of the NM790 using tools like BitLocker, hardware encryption is the preferred method for those that want the highest level of security.
Security is one of the only areas where the NM790 might not be suitable for a specific ecosystem, but for the majority of users who choose not to encrypt everything, it’s something of a non-issue.
Up to 7400MB/s sequential read
Up to 6500MB/s sequential write
As with many NVMe designs, the makers quote slightly different speeds across the range of capacities. The 512GB model is only rated for sequential reads of 7200MB/s and sequential writes of up to 4400MB/s. Where the 1TB and 2TB drives both offer the same sequential reading at 7400MB/s and sequential writes at 6500MB/s.
For this reason and the relatively low price of the 1TB drive, we’d avoid the 512GB option.
All our testing was performed on the 2TB drive, and it lived up to its billing as a very modern and effective NVMe design.
The TBW of these drives scales with capacity, offering 500TB on the 512GB drive, 1000TB on the 1TB and 1500TB on the 2TB. I’m not sure why the 2TB drive isn’t rated for 2000TB TBW, but 1500TB is a decent lifespan. To put that in perspective, writing the 50GB contents of the Blu-ray drive each day to the 1TB drive should be possible for 20,000 days, or nearly 55 years. And, even if you write 1TB each day, the 2TB drive should last five years or more before the NAND is exhausted.
Using the 2TB drive as an example, the NM790 has a better TBW than the Samsung 990 Pro, nearly double that of the Kioxia Exceria Pro, and only 100TB less than the Kingston KC3000.
In performance terms, it’s best to consider this drive in the context of budget drives like the Crucial P5 Plus and WD Black SN770, as it costs roughly the same. However, in some benchmarks, this drive performs much closer to premium branded products, especially in “real world” tests.
Using CrystalDiskMark 8.04, the NM790 is very competitive for sequential reads and writes, good at random reads but is down the list for random writes. Using the Real World profile, the NM790 delivers one of the best sequential read performances we’ve seen, and the write performance is acceptable.
Using the ATTO Disk Benchmark, read speeds are at the higher end of the scale, and the write speed is only marginally less than the premium products. For numerous reasons, the PCMark10 Quick Storage benchmark loves the Samsung 990 Pro, but the NM790 scores higher than the Seagate FireCuda 530.
Our last graph shows maximum power consumption, something that would be critical for laptop users that rely on battery power. It wins this test by a country mile, using only 3.5W at peak.
Overall, the results are generally impressive, considering the cost of this module, and unless you need something with ridiculous IOPs or PCIe Gen 5, this is a good choice and great value for money.
Price & availability
Considering that there are many Gen 4 drives that the NM790 is faster than, it would be reasonable to expect premium pricing, but this drive is shockingly cheap.
At the time of writing, UK pricing on Amazon for the 512GB version is £44.00, the 1TB model is £64.99, and the 2TB is only £119.99, with similar options on eBuyer.
Pricing in the USA is expected to be ‘around the same’ when the NM790 launches there in June.
It’s much cheaper than the Samsung 990 Pro or Seagate FireCuda 530, even if it performs much the same in a desktop system. The WD Black SN770 is cheaper, but it only has a 5150 MB/s read speed.
The Crucial P5 Pro is almost identically priced to the NM790, but has lower read and write speeds and a lower TBW.
Check out our full ranking of the best SSDs for more options.
The NM790 design and price point firmly puts Lexar alongside the likes of Samsung, Crucial, Seagate, and Kingston for offering high-performance NVMe modules with excellent specifications.
Where this drive is especially desirable is the reduced power consumption, making it something of a no-brainer for laptop enhancements.
There are only two disappointments: the first is the lack of hardware encryption; and the second is the lack of a 4TB model at launch. Beyond those two points, this is an excellent choice for high-speed storage and should work equally well inside a PC or a PS5.
Unless you are willing to try a lesser-known brand, in terms of value for money, the Lexar NM790 is a fantastic deal, and its specification makes it the obvious choice for laptop upgrades.
Interface: NVMe 2.0 M.2(2280) PCIe Gen 4.0 x4
Speed: 7400MB/s read, and 6500MB/s write (on 1TB and 2TB)
Capacities: 512GB, 1TB, 2TB
TBW: 500TB (512GB), 1000TB (1TB), 1500TB (2TB)
Dimensions: 80 x 22 x 2.45 mm
Weight: 6 g
Operating temperature: 0-70C
Max power consumption: 3.5W
Warranty/support: limited 5-year warranty within the scope of the TBW
Mark is an expert on displays, reviewing monitors and TVs. He also covers storage including SSDs, NAS drives and portable hard drives. He started writing in 1986 and had contributed to MicroMart, PC Format, 3D World among others.