The Lexar NM620 ($89.99 list for the 512GB version tested), a midrange internal M.2 SSD, has faster sequential read/write speeds than the Lexar NM610, which we reviewed a year ago. Like its predecessor, it did very well on a smattering of our benchmark tests, in this case turning in high 4K read and write scores. However, it foundered on others, has a low durability rating for a TLC-based drive, and is a bit pricey for what it offers. For most upgraders, it will suffice for everyday use, but discriminating power users will want to scout out this drive only if on discount, on a cost-per-gigabyte basis.
Mainstream TLC, Plus PCIe Three
Based on 96-layer triple-level-cell (TLC) NAND flash, the Lexar NM620 employs the NVMe protocol over a four-lane PCI Express (PCIe) 3.0 bus and features an Innogrit controller. (Check out our SSD dejargonizer to make sense of those terms and acronyms.) The drive is manufactured in an M.2 Type-2280 (80mm long) “gumstick” format, commonly seen on internal SSDs.
The drive comes in three capacities: 256GB, 512GB, and 1TB. (Only the latter two are available in the US as of this writing.) Lexar backs the NM620 with a five-year warranty, which is a nice boost up from the NM610’s three-year coverage. The company doesn’t offer any storage-management or encryption software for the drive, so if you want those, you will have to use a third-party offering.
The NM620’s durability ratings, as measured in terabytes written (TBW), match those we saw with the Lexar NM610, and are considerably lower than what we expect from a TLC-based drive. (The TLC-based WD Blue SN550 has durability ratings that are nearly as low—300TBW for the 500GB version, and 600TBW for 1TB—but it sells for considerably less than the NM620.) The ratings look closer to those we generally see with drives based on less-durable QLC memory. For instance, the Editors’ Choice-winning Intel SSD 670p, a QLC-based drive, is rated at just 185TBW for 512GB and 370TBW for its 1TB model.
There are plenty of pricier PCI Express 3.0 x4 drives on the market, but the Lexar NM620 is no great bargain, either. At the 512GB capacity we tested, the drive’s cost is 18 cents per gigabyte, and the 1TB version runs 16 cents per gig. This is higher than the Editors’ Choice-winning Samsung SSD 980, which goes for 14 cents per gig for its 500GB version and 13 cents per gig for the 1TB model, and a tad higher than the Intel SSD 670p, which runs 17 cents per gigabyte for its 512GB model and 15 cents per gigabyte for the 1TB version. The value-oriented WD Blue SN550 runs 13 cents per gig for 500GB and just 10 cents a gigabyte for the 1TB version.
Testing the Lexar NM620: A Mixed Bag of Scores
We test all of our Serial ATA (SATA) and PCI Express 3.0 SSDs on PC Labs’ main storage testbed, which is built on an Asus Prime X299 Deluxe motherboard with an Intel Core i9-10980XE Extreme Edition CPU. We use 16GB of DDR4 Corsair Dominator RAM clocked to 3,600MHz, and the system employs Nvidia’s GeForce RTX 2080 Ti Founders Edition as its discrete graphics card. (See more about how we test SSDs.) PCIe 4.0 SSDs are tested on a different, AMD Ryzen-based testbed with 4.0 support.
PCMark 10 Overall Storage and Trace-Based Tests
The overall PCMark 10 storage test, from UL—the world’s leading independent benchmark developer—runs a full suite of typical drive-access tasks. The Overall Storage Test scores below represent how well a drive does throughout the entire PCMark 10 run. It’s the sanctioned score presented by UL’s software at the end of each run.
After that are some more granular measures that we extract, derived from PCMark 10’s background “traces.” These following PCMark 10-derived tests represent a simulation of how quickly a drive is capable of launching a particular program (or, in the first case, booting Windows 10). The Windows 10 trace simulates the full Windows 10 operating system startup procedure and records how quickly the drive can feed the kind of data requested.
After that is a game-launching test set, which simulates how quickly a drive can read shallow-depth small random 4K packages, one of the more commonly used file-block sizes for game installations. Although file block size depends on the title you’re playing, 4K small random read is the most accurate block-size metric relevant to these three popular FPS titles: Battlefield 5, Overwatch, and Call of Duty: Black Ops 4.
The drives are also put through an important test for creative types. As anyone who regularly works in programs like Adobe Premiere or Photoshop can tell you, a constant pinch point is the time it takes for these programs to launch.
Finally, the PCMark 10 copy tests are also derived from PCMark 10 traces. At first, these numbers might look low compared with the straight sequential-throughput numbers achieved in benchmarks like Crystal DiskMark 6.0 and AS-SSD, which are charted below the PCMark 10 results. But that’s due to the way this score is calculated and the nature of (and differences between) the source data sets.
The NM620 turned in a middling score on the PCMark 10 overall storage test, with some of the better four-lane PCI Express 3.0 drives such as the Samsung SSD 980, Intel SSD 670p, WD Blue SN550, and Crucial P5 roundly surpassing it. Its PCMark 10 trace scores were unimpressive; for one, it had the low score on the game-launching test for Call of Duty: Black Ops 4.
Sequential Speed and Copy Tests
Moving on from PCMark 10-derived numbers, the Crystal DiskMark 6.0 sequential tests simulate best-case, straight-line transfers of large files. After that is a series of file and folder transfers done in the SSD benchmarking utility AS-SSD. This trio of tests involves copying large files or folders from one location on the test drive to another.
Lexar’s rated read/write speeds for the NM620’s 512GB version are up to 3,300MBps read and 2,400MBps write. It tested close to this on the Crystal DiskMark 6.0 sequential speed benchmarks, turning in 3,155MBps read and 2,387MBps write scores.
Crystal DiskMark’s 4K (or “random read/write”) tests simulate typical processes involved in program/game loads or bootup sequences. The 4K read test was the one benchmark in which the Lexar NM610 had excelled when we tested it last year, turning in the high score among the drives we compared it with. The NM620 flipped the script, turning in the high score in the 4K write part of the test—barely beating out several other drives in doing so—while posting an average 4K read score. The NM620 also turned in a high score in the AS-SSD game-folder copy test, and did very well in AS-SSD’s ISO-image-file copy-speed trial.
Only an Incremental Upgrade
The Lexar NM620 internal SSD represents an improvement over its predecessor, the NM610, with faster sequential read-write speeds and a longer warranty. The NM620 was inconsistent in our testing, showing flashes of brilliance by acing the Crystal DiskMark 4K write and some AS-SSD copy tests, but proving unimpressive on PCMark 10 testing and turning in the lowest score on one game-launching test.
The drive is a little pricey for what it offers and has a low durability rating for a TLC-based SSD, but it should be fine for general-purpose use. For both performance and value in a PCI Express 3.0 internal SSD, our top pick is still the Samsung SSD 980.
