Lexar NM790 4TB PCIe Gen4 NVMe SSD Review

Lexar NM790 4TB
Lexar NM790 4TB

Today, we are looking at the Lexar NM790 4TB SSD. This is the third Lexar drive I have reviewed, and I was previously impressed by the NM800 Pro. The NM790 is an interesting drive in that it is billed as a high-performance drive that is DRAM-less, which is an unusual combination that is a claim that we will have to test.

Lexar NM790 4TB NVMe SSD

The Lexar NM790 4TB comes in a single-sided M.2 2280 (80mm) form factor. This drive is also available with a heatsink included, but my review sample is only the bare drive.

Lexar NM790 4TB Front
Lexar NM790 4TB Front

The NM790 sports a Mapio MAP1602 controller, which I recently saw on the Fanxiang S880. Similar to the S880, the NAND is also YMTC 232-layer TLC, and as mentioned in the introduction, there is no DRAM cache.

Lexar NM790 4TB Back
Lexar NM790 4TB Back

The rear of the NM790 has nothing but a product label.

Lexar NM790 SSD Specs

The spec sheet says the Lexar NM790 is available between 512GB and 4TB capacities.

Lexar NM790 4TB Specs
Lexar NM790 4TB Specs

We have the 4TB model on hand, which lists high-end sequential transfer speed specs for a PCIe Gen 4 drive at 7400 MB/s read and 6500 MB/s write. This is essentially as fast as a Gen 4 drive can get, give or take 100 MB/s or so. It is also a pretty bold claim for a DRAM-less drive, especially on the write speed. The endurance for this drive is good, rated at 3000 TBW. My standard for good endurance is around 600 TBW per 1 TB of drive capacity, and the NM790 comes in at or above that point for all capacity levels. Lexar also includes a 5-year warranty, which is the industry standard for a quality drive at this point.

Lexar NM790 4TB CrystalDiskInfo
Lexar NM790 4TB CrystalDiskInfo

CrystalDiskInfo can give us some basic information about the SSD and confirms we are operating at PCIe Gen4 x4 speeds using NVMe 2.0.

Test System Configuration

We are using the following configuration for this test:

  • Motherboard: MSI MAG X670E Tomahawk
  • CPU: AMD Ryzen 9 7900X (12C/24T)
  • RAM: 2x 16GB DDR5-6000 UDIMMs

Our testing uses the Lexar NM790 4TB as the boot drive for the system, installed in the M.2_1 slot on the motherboard. This slot supports up to PCIe Gen 5 x4. The drive is filled to 85% capacity with data, and then some is deleted, leaving around 60% used space on the volume.

Next, we are going to get into our performance testing.


  1. Just a heads up. There is a problem with Linux as it fails to initialize (nvme0: Device not ready). I think it is solved from kernel 6.5.x

  2. Yeah, 4TB single-sided was what drew me to buy this drive for use as my D: for my games library. Have been running it a couple weeks now and zero complaints.

  3. How does this drive measure up to other gen4 drives temperature-wise, being singlesided and DRAM-less? I would expect it also run quite a bit cooler? This is much more important in sub-notebook/portable environments that may still need large capacity.


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