# Lexar NM790 4TB Review — 4 TB of DRAM-less PCIe 4.0 Speed (2026)

The Lexar NM790 4TB combines 7,400 MB/s reads, 6,500 MB/s writes, and 3,000 TBW endurance on a single-sided PCIe 4.0 board that slots straight into a PS5.

Quick answer: Buy the Lexar NM790 4TB when the point of the drive is room: a full game library, a PS5 that no longer juggles installs, or a video archive that needs Gen4 speed without flagship trade-offs. Skip it if your days are filled with sustained multi-hundred-gigabyte writes — the WD Black SN850X 4TB, with its 2 GB of DRAM and stronger random performance, is the calmer tool for scratch-disk duty. Within Lexar's own range, the 4TB is the sweet spot: the 8 TB model adds room but gives up rated speed, while the 2 TB halves the endurance budget. For PCIe 4.0 bulk storage in 2026, this is one of the most complete packages on the market.

## Specifications

| Specification | Value |
| --- | --- |
| Capacity | 4 TB |
| Interface | M.2 4.0 x 4 |
| Controller | Maxiotech MAP1602A |
| Memory type | YMTC 232-L TLC |
| DRAM cache | No |
| Sequential read | 7400 MB/s |
| Sequential write | 6500 MB/s |
| Random read IOPS | 900000 |
| Random write IOPS | 900000 |
| Endurance | 3000 TBW |
| MTBF | 1500000 |
| Warranty | 5 years |

## Performance

Lexar rates the 4TB NM790 at 7,400 MB/s sequential reads and 6,500 MB/s writes over PCIe 4.0 x4, with random performance rated up to 900K IOPS in both directions. Those are manufacturer figures, but credible ones: ServeTheHome tested the 4TB as a boot drive on a Ryzen 9 7900X platform and judged its rated speeds essentially as fast as a Gen4 drive can get, give or take 100 MB/s. In practice that means DirectStorage titles and PS5 games load well past Sony's 5,500 MB/s recommendation, and 4K video imports or library-wide file moves finish in seconds rather than minutes.

The sustained picture carries the usual DRAM-less caveats. Writes ride a dynamic SLC cache, and once it fills during a very large transfer, throughput drops back to native TLC rates for the remainder — a non-event for game installs and boot duty, but visible when hundreds of gigabytes move in one session. Thermals also deserve attention at 4 TB, because the NAND population is denser on the same single-sided layout; testing across the NM790 line has documented thermal throttling during extended SNIA stress writes, so a motherboard heatsink or the bundled-heatsink variant is the smart setup. Within those limits, reviewers consistently find the drive indistinguishable from pricier Gen4 competitors in everyday use.

## Endurance, TBW & Warranty

Lexar covers the NM790 4TB with a 5-year limited warranty rated to 3,000 TBW, whichever limit comes first. That endurance budget works out to roughly 600 TBW per terabyte — ServeTheHome's benchmark for a healthy modern TLC drive — and at a demanding 40 GB of writes per day it would take more than two centuries to exhaust. The rated MTBF is 1.5 million hours, a fleet-level statistic rather than a promise for any individual drive. Sudden power-loss protection, wear leveling, and bad-block management run in firmware, and hardware AES-256 encryption is built in. The same 5-year terms apply line-wide, with 1,500 TBW at 2 TB and 1,000 TBW at 1 TB; claims are handled through Lexar directly in most regions.

## Pros and Cons

**Pros:**

- 7,400 MB/s reads and 6,500 MB/s writes
- 3,000 TBW endurance with a 5-year warranty
- Single-sided PCB even at 4 TB capacity
- NVMe 2.0 protocol support
- AES-256 encryption with TCG Opal 2.0
- Rated up to 900K random-read and write IOPS
**Cons:**

- No DRAM cache on the PCB
- No heatsink included on the base model
- SLC cache exhaustion slows very large transfers
- Thermal throttling without added cooling under sustained load


## Verdict

Buy the Lexar NM790 4TB when the point of the drive is room: a full game library, a PS5 that no longer juggles installs, or a video archive that needs Gen4 speed without flagship trade-offs. Skip it if your days are filled with sustained multi-hundred-gigabyte writes — the WD Black SN850X 4TB, with its 2 GB of DRAM and stronger random performance, is the calmer tool for scratch-disk duty. Within Lexar's own range, the 4TB is the sweet spot: the 8 TB model adds room but gives up rated speed, while the 2 TB halves the endurance budget. For PCIe 4.0 bulk storage in 2026, this is one of the most complete packages on the market.

## Frequently Asked Questions

### Is the Lexar NM790 4TB compatible with the PS5?

Yes. Sony's published criteria ask for a PCIe 4.0 NVMe drive with a 5,500 MB/s or faster recommended read speed and a heatsink that keeps total dimensions within 110 × 25 × 11.25 mm. The Lexar NM790 4TB reads at 7,400 MB/s and, unusually for a 4 TB drive, is single-sided at just 2.45 mm thick, so a slim heatsink fits easily inside the size window. Lexar officially lists the range as PS5-compatible and sells a pre-cooled NM790 with Heatsink variant for a drop-in install.

### Is the Lexar NM790 4TB good for gaming?

For gaming, 4 TB is where an NM790 stops being a boot drive and becomes a library. Modern AAA titles routinely pass 100 GB each, so a 4 TB pool holds dozens of installs without the uninstall-reinstall cycle smaller drives force. The 7,400 MB/s read rating clears Sony's 5,500 MB/s PS5 recommendation by a wide margin, and DirectStorage titles benefit from the full PCIe 4.0 link. DRAM-less operation has no measurable effect on game loading, since reads are exactly the workload HMB and SLC caching handle well.

### Does the Lexar NM790 4TB have a DRAM cache?

No — there is no physical DRAM chip on the board. The Maxio MAP1602 platform uses Host Memory Buffer 3.0, borrowing a portion of system memory for the flash translation tables, while a dynamic SLC cache carved from the NAND absorbs bursts of writes. For desktops, laptops, and the PS5, responsiveness is nearly identical to DRAM-equipped drives in consumer workloads. The gap appears in sustained mixed write sessions and heavy random workloads, where DRAM designs such as the WD Black SN850X with its 2 GB of cache keep performance more even.

### What is the TBW endurance of the Lexar NM790 4TB?

The 4 TB model is rated at 3,000 TBW under a 5-year limited warranty, whichever limit arrives first. That is roughly 600 TBW per terabyte, the level ServeTheHome cites as the healthy baseline for current TLC drives, and it doubles the 2 TB model's 1,500 TBW rating. Written out, 3,000 TBW is about three petabytes of total writes; even at a punishing 40 GB per day, exhaustion would take over two centuries.

### How does the Lexar NM790 4TB compare to the 2 TB model?

Rated speed is identical: both capacities carry 7,400/6,500 MB/s sequential figures on the same MAP1602 and YMTC 232L platform. The 4 TB pulls ahead in three ways — endurance doubles from 1,500 to 3,000 TBW, the protocol steps up from NVMe 1.4 to NVMe 2.0, and total capacity obviously doubles as well. What the 2 TB offers instead is a lower cost per drive and slightly lighter thermals with two NAND packages instead of four. If the budget stretches to 4 TB, it is the stronger long-term pick.

### Lexar NM790 4TB or WD Black SN850X 4TB — which wins?

They split the decision. The SN850X counters with 2 GB of DRAM, slightly higher rated write speed at 6,600 MB/s versus 6,500 MB/s, and stronger random performance at 1,200K/1,100K IOPS, which matters for sustained scratch-disk and professional workloads. The NM790 4TB answers with a higher 3,000 TBW endurance rating against 2,400 TBW, a single-sided PCB that fits consoles and thin laptops more easily, and DRAM-less efficiency. Choose the WD for heavy sustained writes; choose the Lexar for capacity, endurance headroom, and placement flexibility.

### Does the Lexar NM790 4TB need a heatsink?

For PS5 installation, yes — Sony requires a heatsink on every internal upgrade, and the single-sided 4 TB board leaves the full height budget for one within the 11.25 mm limit. On a desktop, a motherboard heatsink is recommended: testing across the NM790 line has shown thermal throttling during extended sustained-write stress tests on bare drives. Inside a well-ventilated laptop, the drive usually manages on its own. Buyers who prefer zero assembly can pick Lexar's NM790 with Heatsink variant, which arrives pre-cooled.

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Last updated: 2026-09-05. Source: https://ssdrive.net/lexar-nm790-4-tb