Lexar NM790 4TB SSD Review

The last Lexar SSD we looked at was the Professional NM800 Pro at the beginning of 2023 (HERE). Now we have their latest drive, the NM790 which is part of Lexar's range of gaming products. This Gen4 x4 drive comes in four capacities; 512GB, 1TB, 2TB and the 4TB flagship drive we are reviewing here.

The Professional NM800 Pro used a rarely seen controller, the InnoGrit Rainier IG5236, and the NM790 follows the same path with an even rarer controller (to our eyes anyway) in the form of the Maxiotech MAP1602A. Built on a 12nm TSMC process with ARM Cortex-R5 architecture the MAP1602A is a four-channel controller that is a DRAM-less design which uses Host Memory Buffer (HMB) 3.0 technology making use of system memory instead of a dedicated cache chip. The drive also makes use of Dynamic SLC cache writing technology. Intestingly the controller uses a 2400 MT/s interface speed which is somewhat of a rarity amongst DRAM-less designs.

The NAND the drive uses is another rarely seen item, namely Longsys NAND. Longsys are Lexar’s parent company and the 4TB NM790 uses four 1TB 232-layer 3D TLC NAND packages.

Lexar rates the Sequential performance for the 4TB version of the NM790 as up to 7,400MB/s for reads and 6,500MB/s for writes. Using the ATTO benchmark we couldn't quite hit those maximum figures with test results of 6,920MB/s and 5,960MB/s for reads and writes respectively. That tested read result of 6,920MB/s is the third fastest ATTO read figure we've seen to date for a Gen4 consumer drive behind Lexar's own Professional NM800 Pro (Heatsink version) and HP's FX900 Pro. Switching over to the CrystalDiskMark 8 benchmark saw confirmation of the official figures using the benchmark's default setting with a best-read figure of 7,437MB/s with writes a little shy of the official maximum at 6,439MB/s but still very much in the ballpark.

Oddly, Lexar doesn't mention the 4K performance of the NM790 on the specification page for the drive on their website. But the Maxiotech MAP1602A controller is rated as up to 1,000K for both reads and writes. The best figures we saw with our four treaded testing was 620,827 IOPS (QD32) for reads and 518,199 IOPS (QD32) for writes. In our four thread tests, the drive is the fastest we've seen to date for any consumer drive at QDs 1, 2 and 32 when it comes to random reads and the fastest at QD32 when it comes to random writes. However, with the more aggressive settings of CrystalDiskMark 8 Peak Performance Profile, we saw speeds of 931,606 IOPS and 1,048,635 IOPS for reads and writes, respectively.

Lexar's NM790 is a very fast drive and in some of our tests, it is the fastest consumer drive we've seen to date, however the flipside of all that performance is heat generation. PCIe Gen4 drives are known for producing high temperatures when pushed hard and the 4TB Lexar NM790 is certainly no exception to that. Indeed in a couple of our test runs (CrystalDiskMark 8 Sequential QD1-32 T1 Write test and the ATTO tests), the drive hit 68 °C which is just 2°C away from the stated maximum operating temperature of 70°C and that was with the drive under the chunky passive heatink that our test motherboard, Gigabyte's AORUS X670E Xtreme uses. We did run the drive without any dedicated motherboard cooling in place during an ATTO test run, which saw  the drive hit 75°C so it's not something we would recommend.

The NM790 is also supported by Lexar's SSD Dash. It might not have the funky GUI of some of its competitors' utilities but does have all the basics to help you maintain the drive including the ability to perform firmware updates, Secure Erase and data migration.

We found the 4TB version of Lexar's NM790 for £187.98 (inc VAT) on Ebuyer.co.uk HERE

Pros

• Very fast drive.
• 4TB capacity.
• Endurance.
• Pricing.

Cons

• Really needs a heatsink.
• Write speeds in some benchmark tests.

KitGuru says: Lexar's latest Gen4 drive performs very well and in some of our testing it was the fastest drive we've seen to date. It does need some serious cooling if you are planning to push it hard, however. Still, Lexar has given it every chance in the marketplace with some extremely competitive pricing.

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