Lexar NM790 1TB PCIe Gen4 NVMe SSD: features, specs and who it suits

The Lexar NM790 is an M.2 2280 solid state drive that connects over PCIe Gen4 x4 using the NVMe protocol. The 1TB version (LNM790X001T-RNNNU) is aimed at gamers and creators, and Lexar says it works in desktop computers, laptops and the PlayStation 5. Here is what the main specifications mean.

PCIe Gen4 speed

Lexar rates the drive at up to 7,400 MB/s for reads and 6,500 MB/s for writes. It also says this is twice as fast as PCIe Gen3 SSDs. Those are peak sequential figures, best seen when copying large files. Everyday tasks such as opening applications depend more on responsiveness than on peak speed, and the real result depends on the rest of the system. A motherboard or laptop slot must support PCIe Gen4 to reach the top speeds; in an older Gen3 slot the drive would run slower.

Host Memory Buffer and caching

Many drives use a small amount of DRAM on the drive to keep track of where data is stored. Lexar says the NM790 uses Host Memory Buffer (HMB) 3.0, which lets the drive borrow a little of the computer's own memory for that job, along with a Dynamic SLC Cache. SLC caching treats part of the memory as fast single-bit storage so short bursts of writing complete quickly. Lexar says this approach gives smoother transfer speeds and uses up to 40% less power than Gen4 SSDs with a DRAM cache, which matters for laptop battery life and heat.

Endurance and warranty

The 1TB model is rated at 1,000 TBW, meaning terabytes written, a measure of the total data the maker expects the drive to handle. Lexar also lists a five-year limited warranty. For most home and creative use, that is a generous allowance.

Fitting laptops, desktops and the PS5

The drive is single-sided, which Lexar says makes it suitable for laptops, where space under the cover can be tight. The M.2 2280 size (22 mm wide, 80 mm long) is the standard for most desktop motherboards and many laptops. Lexar lists compatibility with the PlayStation 5, which needs a heatsink in its expansion slot. Check Sony's requirements for heatsink height and the console's firmware, and see Lexar's notes on PS5 installation.

Who it suits

It suits people upgrading from a SATA drive or an older NVMe drive, gamers who want quick load times, and creators moving large photo or video files. A 1TB capacity is a good size for an operating system, applications and a handful of current games; larger libraries may call for a bigger drive.

What to check before you buy

• Slot: confirm your device has an M.2 2280 slot with NVMe and PCIe support.
• Generation: a PCIe Gen4 slot is needed for the full speed.
• Cooling: check whether your motherboard, laptop or console needs a heatsink.
• Capacity: the 1TB label is in decimal units, so the operating system shows slightly less.
• PS5 use: check the console's current compatibility notes before installing.
• Backups: keep copies of important files elsewhere.

The short version

• A 1TB M.2 2280 PCIe Gen4 x4 NVMe SSD from Lexar, model LNM790X001T-RNNNU.
• Rated at up to 7,400 MB/s read and 6,500 MB/s write, with 1,000 TBW.
• Uses HMB 3.0 and a Dynamic SLC Cache; single-sided for laptops.
• Compatible with the PS5, according to Lexar.
• Comes with a five-year limited warranty.

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