Introduction

Lexar has made a name for itself in the portable storage market—they are very well known for their SD cards and USB drives, so it's natural for Lexar to expand into other areas of flash storage, like consumer SSDs. Founded as a subsidiary of Micron, Lexar was sold to the Chinese parent company Longsys in 2017 and has been operating independently since.



Today we have on the testbed the Lexar NQ780 4 TB, which is a high-capacity M.2 NVMe drive at a competitive price. This SSD uses the older Innogrit IG5236 controller, paired with QLC NAND flash from Intel. This hardware combo looks a bit like there was some surplus inventory left and Lexar snapped up both at a good price, building the NQ780 from it. As host interface, PCI-Express 4.0 is used. Considering that this is a cost-optimized SSD, it's not unexpected that there is no DRAM cache available.

The Lexar NQ780 is available in capacities of 1 TB ($73), 2 TB ($135) and 4 TB ($240). The endurance is set to 600 TBW, 1200 TBW and 2400 TBW respectively. Lexar includes a five-year warranty with the NQ780 SSD.

Packaging

The Drive

The drive is designed for the M.2 2280 form factor, which makes it 22 mm wide and 80 mm long.


PCI-Express 4.0 x4 is used as the host interface to the rest of the system, which doubles the theoretical bandwidth compared to PCIe 3.0 x4.


On the PCB you'll find the controller and four flash chips, a DRAM cache chip is not available.


Lexar's sticker uses a white sticky tape that makes contact with the chips and has a shiny metal foil on top of that. This means less heat transfer, because heat has to travel through the white plastic adhesive first. The metal foil is also rather thin.

Chip Component Analysis

The Innogrit IG5236 is the company's first controller to support PCI-Express 4.0, released in 2020. It uses eight channels to maximize transfer rates and is fabricated on a 12 nm process at TSMC Taiwan.


The four flash chips are Intel QLC NAND with 144 layers. Each chip has a capacity of 1 TB.

Test Setup

Synthetic Testing

• Tests are run with a 20-second-long warm-up time (result recording starts at second 21).
• Between each test, the drive is left idle for 60 seconds, to allow it to flush and reorganize its internal data.
• All write requests contain random, incompressible data.
• Disk cache is flushed between all tests.
• During these tests, M.2 drives are tested with additional active fan-cooling, to ensure thermal throttling can't happen

Real-life Testing

• After initial configuration and installation, a disk image is created; it is used to test every drive.
• Automated updates are disabled for the OS and all programs. This ensures that—for every review—each drive uses the same settings, without interference from previous testing.
• Our disk image consumes around 700 GB—partitions are resized to fill all available space on the drive.
• All drives are filled with random data to 85% of their capacity. This is intentional, to run the drive in realistic operating conditions—nobody uses a nearly-empty SSD in their system. It also puts additional stress on the pseudo-SLC cache subsystem, because there is less free NAND space to work with.
• Partitions are aligned properly.
• Disk cache is flushed between all tests.
• In order to minimize random variation, each real-life performance test is run several times, with reboots between tests to minimize the impact of disk cache.
• All application benchmarks run the actual application and do not replay any disk traces.
• Our real-life testing data includes performance numbers for a typical high-performance HDD, using results from a Western Digital WD Black 1 TB 7200 RPM 3.5" SATA. HDDs are significantly slower than SSDs, which is why we're not putting the result in the chart, as that would break the scaling, making the SSDs indistinguishable in comparison. Instead, we've added the HDD performance numbers in the title of each test entry.
• During these tests, M.2 drives are tested with additional active fan-cooling, to ensure thermal throttling can't happen