Lexar NM990 4TB PCIe 5.0 NVMe SSD Review (2026)
The Lexar NM990 4TB tops the brand's budget PCIe 5.0 line, pairing a DRAM-less Maxio MAP1806A controller with Longsys TLC for 14,000 MB/s reads and 11,000 MB/s writes.
Controller & Memory
The Lexar NM990 is the brand's value PCIe 5.0 drive, built to bring Gen5 sequential read speeds down to a much lower price point than DRAM-equipped flagships. The 4 TB model reviewed here is the largest capacity of the NM990 range, which runs from 1 TB to 4 TB, and it pairs Maxio's MAP1806A 8-channel controller with Longsys 3D TLC NAND. The defining design choice is that the NM990 is a DRAM-less drive: instead of a dedicated DRAM cache it uses HMB (Host Memory Buffer), borrowing a small slice of system memory to manage the flash translation layer, which keeps cost and power draw down at the expense of some sustained random performance.
The 4 TB gets the family's strongest write speed alongside its maximum capacity. Lexar rates every NM990 capacity at up to 14,000 MB/s sequential read, and the write rating scales with capacity, so the 4 TB reaches the family's highest 11,000 MB/s sequential write, ahead of the 2 TB's 10,000 MB/s and the 1 TB's 7,500 MB/s. That scaling reflects the DRAM-less design, where more NAND die in parallel at larger capacities lift the write speed. The 4 TB carries a 2,400 TBW endurance rating, a five-year warranty and the full 14,000 MB/s read figure, making it the variant of choice for buyers who want both a large capacity and the best write performance the NM990 platform offers.
As a budget Gen5 part the NM990 competes less with DRAM flagships like Lexar's own NM1090 Pro and more with other value PCIe 5.0 and high-end PCIe 4.0 drives, where it trades a DRAM cache for a low Gen5 sticker price. The drive ships in a standard M.2 2280 form factor with a heatsink included, a thoughtful touch for a Gen5 part given how hot the platform runs. For a buyer who needs a large fast capacity plus the NM990's best write speed on a budget, the 4 TB is the top of the range, with the usual note that the 2 TB is the value sweet spot for most buyers.
Storage Comparisons:
NM990 Performance & Benchmarks
Lexar rates the NM990 4 TB at up to 14,000 MB/s sequential read and 11,000 MB/s sequential write, the highest write figure in the NM990 family. The read speed matches far more expensive Gen5 flagships, so for game loads, large file reads and DirectStorage-enabled asset streaming the drive feels genuinely fast, while the 11,000 MB/s write figure is the best in the range thanks to the most NAND die in parallel. Every NM990 capacity shares the 14,000 MB/s read rating, while write scales from 7,500 MB/s on the 1 TB up to 11,000 MB/s on the 4 TB, placing the flagship write speed on the largest capacity.
Lexar NM990 4 TB vs M.2 5.0 peers
Switch between sequential throughput and random IOPS to see how this drive stacks up against other M.2 5.0 SSDs in our database. The highlighted bar is the drive on this page — click any other bar to open that drive.
- Corsair MP700 Pro XT 1 TB: 14,900 MB/s read, 14,200 MB/s write
- Corsair MP700 Pro XT 2 TB: 14,900 MB/s read, 14,500 MB/s write
- Corsair MP700 Pro XT 4 TB: 14,900 MB/s read, 14,400 MB/s write
- Crucial T710 1 TB: 14,900 MB/s read, 13,800 MB/s write
- Lexar NM990 4 TB (this drive): 14,000 MB/s read, 11,000 MB/s write
Because the NM990 is DRAM-less and relies on HMB, sustained random performance under heavy mixed workloads is lower than on DRAM-equipped drives, though for everyday desktop use and gaming the difference is rarely noticeable. The drive does not publish prominent random IOPS figures, which itself signals the value positioning. The Maxio MAP1806A is an 8-channel PCIe 5.0 controller, so the sequential throughput is real rather than aspirational, and the included heatsink helps it hold speed under load. For a 4 TB drive used for bulk fast storage plus a boot and game volume on a PCIe 5.0 platform, the NM990 delivers the family's best write speed alongside maximum capacity at a budget price.
Lexar NM990 vs Competitors
See how the NM990 stacks up against other M.2 5.0 drives in our database:
Compare with rival drives:
Endurance, TBW & Warranty
Lexar backs the NM990 with a five-year limited warranty, and the 4 TB model carries a 2,400 TBW (terabytes written) endurance rating, the highest in the lineup. That is strong coverage for a budget Gen5 drive: 2,400 TBW works out to roughly 1,315 GB of writes every single day for five years, staggeringly more than a typical 20 to 50 GB daily consumer workload. At 50 GB of writes per day you would need around 131 years to exhaust the rated endurance, so the NAND will outlast the warranty term many times over and wear is simply not a concern, even on a 4 TB drive holding a large media library. The five-year term is the binding limit, and it is generous for a value Gen5 drive where three-year cover is common. As an established brand Lexar offers a global support and RMA network, so keep your proof of purchase. The DRAM-less design means heavy sustained-write workloads are not this drive's strength, but endurance itself is not a realistic concern within the five-year window.
Lexar NM990 4 TB Specifications
| Category | Value |
|---|---|
| Capacity [?] | 4 TB |
| Interface [?] | M.2 5.0 |
| Controller [?] | MaxioTech MAP1806A 8 Channel |
| Memory type [?] | Longsys TLC |
| DRAM [?] | HMB (no DRAM) |
| Read speed (MB/s) [?] | 14000 |
| Write speed (MB/s) [?] | 11000 |
| Read IOPS [?] | n/a |
| Write IOPS [?] | n/a |
| Endurance (TBW) [?] | 2400 |
| MTBF (million hours) [?] | 2000000 |
| Warranty (years) [?] | 5 |
Verdict: Is the NM990 Worth It in 2026?
The Lexar NM990 4 TB is the top of the brand's budget PCIe 5.0 line, pairing the value Maxio MAP1806A plus Longsys TLC platform with maximum 4 TB capacity, the full 14,000 MB/s read speed, the family's best 11,000 MB/s write figure, a 2,400 TBW rating, a five-year warranty and an included heatsink. Its strengths are capacity, Gen5 read throughput and the highest write speed in the range, all at a budget price. Its weaknesses are the DRAM-less HMB design and the absence of prominent random IOPS figures. It suits a budget-conscious buyer who wants a large, fast Gen5 drive; most buyers are better served by the 2 TB sweet spot, and anyone who needs sustained random performance should look at a DRAM-equipped Gen5 drive like Lexar's own NM1090 Pro.
+ Pros
- Budget PCIe 5.0 with 14,000 MB/s reads
- 11,000 MB/s write, the highest in the NM990 family
- Maximum 4 TB capacity in a single M.2 slot
- Maxio MAP1806A 8-channel Gen5 controller
- Heatsink included
- 2,400 TBW endurance and 5-year warranty
- Cons
- DRAM-less HMB design limits sustained random performance
- Random IOPS figures not prominently published
- Needs a PCIe 5.0 platform to justify the read speed
- Highest price in the NM990 lineup
Buy this or similar SSD Storage:
Video Review
DON'T BUY Lexar NM790 4TB SSD Before Watching THIS! 🚫💔 (9 Reasons)
