ADATA Legend 840 review: A moderately fast PCIe 4 SSD


ADATA recently launched a new solid-state drive that supports PCI Express Gen 4, promising excellent read and write speeds for a reasonable price. It’s called Legend 840 and it’s available in 512GB and 1TB storage capacities. We received it in testing and we’ve used and benchmarked it for a while. Now, we’d like to share with you our findings so, if you’re interested, read this review to see whether the ADATA Legend 840 PCIe Gen4 x4 M.2 2280 solid-state drive should be on your shopping list:

ADATA Legend 840 PCIe Gen4 x4 M.2 SSD: Who is it good for?

The ADATA Legend 840 solid-state drive is an excellent choice for:

  • People who want to switch to a PCIe 4 solid-state drive
  • Those who want a fast SSD for a reasonable price
  • Users who have computers or laptops that support PCIe 4

Pros and cons

We have quite a few good things to say about the ADATA Legend 840 SSD:

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  • It’s fast, both at reading and writing data
  • It runs on PCI Express 4.0 x4
  • It uses reliable 3D NAND flash memory
  • It comes with a bundled heat spreader that can decrease its temperatures
  • It has a five-year warranty
  • Reasonable price compared to other PCIe 4.0 solid-state drives

As for the downsides, the ones we identified are that:

  • It’s a DRAM-less solid-state drive (there’s no RAM onboard for fast cache)
  • It tends to get quite hot (we measured 64 degrees Celsius with the heat sink in a desktop PC)
Product rating 4/5


The ADATA Legend 840 is a moderately fast PCIe4 solid-state drive that can boost your computer’s speed if you’re upgrading from a PCIe 3 drive. Its data read and write speeds are excellent, and the price ADATA asks for it is reasonable. In our opinion, it’s a good choice for gamers as well as for anyone who wants a fast storage device without breaking the bank.

Unboxing the ADATA Legend 840 PCIe Gen4 x4 M.2 SSD

The ADATA Legend 840 solid-state drive comes in a small rectangular box made of black cardboard. It doesn’t have any cutouts so you can’t see the actual drive before you unbox it, but you can get an idea of what’s inside by looking at the picture on the front.

The package of the ADATA Legend 840

The box also lets you know that the ADATA Legend 840 is an M.2 NVMe solid-state drive running on PCIe Gen4 x4, capable of achieving a read speed of up to 5000MB/s and a write speed of up to 4500MB/s.

ADATA Legend 840: The back of the box

In the package, you’ll only find the solid-state drive and a heat spreader for it, both placed inside and protected by a transparent plastic blister.

Unboxing the ADATA Legend 840 SSD

Unboxing the ADATA Legend 840 solid-state drive is fast and straightforward. We appreciate that the company also bundled a heat spreader with the drive.

Design and hardware specifications

The ADATA Legend 840 is an NVMe 1.4 PCI Express Gen4 x4 solid-state drive that uses an Innogrit IG5220 controller (DRAM-less, which means there’s no RAM memory on the drive for fast cache) that can reach around 5 GBps. And that’s exactly the sequential read speed that ADATA advertises the SSD to support: up to 5000MB/s. The maximum sequential write speed it can reach is a bit lower: 4500MB/s. As for random data read/write speeds, its specs reveal maximum values of 650K/600K 4K random read/write IOPS (Input/Output Operations Per Second). The SSD is available in two capacities: 512GB and 1024GB, the latter being the one we tested.

Information about the ADATA Legend 840 SSD

As you know now from the unboxing section of this review, the Legend 840 solid-state drive also comes with a thin heat sink that, according to ADATA, can reduce temperatures by up to 15%. During our tests, the SSD (with the heat sink mounted) reached up to 64 degrees Celsius, which is a bit high.

For the Legend 840 SSD, ADATA used 3D TLC NAND memory, which means generous storage capacities and low power requirements. It’s also a durable type of flash memory, allowing ADATA to sell the SSD with a 5-years warranty.

The Legend 840 is built on the M.2 2280 form factor: it measures 80 mm × 22 mm (roughly 3 × ¾ in) and weighs 9 grams / 0.32 oz with the heat sink or 6 grams / 0.32 oz without the heat sink mounted. As the M.2 2280 form factor is widely used in most if not all computers, laptops, and even gaming consoles, the solid-state drive offers excellent compatibility in this regard.

If you want to know more about the specs and features of this solid-state drive, visit ADATA Legend 840 PCIe Gen4 x4 M.2 SSD.

ADATA Legend 840 has specs that put it right at the top of the ladder, among the fastest solid-state drives on the market. You get a very fast PCI Express 4.0 controller, NVMe, M.2, long-lasting flash memory, and plenty of storage capacity.

Using the ADATA Legend 840 PCIe Gen4 x4 M.2 SSD

We used and tested the ADATA Legend 840 SSD on a desktop computer with the following configuration:

After we installed the ADATA Legend 840 solid-state drive on our PC, the first thing we wanted to check was how much storage capacity you get if you install Windows 11 on it. You can see in the following screenshot that its real storage space is 953GB when formatted using the default NTFS file system.

The ADATA Legend 840 SSD in Windows 11

Next, we wanted to see the real-life copy speeds offered by the ADATA Legend 840 SSD. To check that, we used another PCIe 4.0 solid-state drive that’s even faster: a 2TB Kingston KC3000 SSD. When we copied a 5.18 GB Windows 11 ISO file onto the Legend 840, we saw an impressive speed that went over 3GB/s.

Copying a large file on the ADATA Legend 840 SSD

Copying the same large file from the ADATA Legend 840 to the other solid-state drive was similarly fast, reaching again more than 3GB per second.

Copying a large file from the ADATA Legend 840 SSD

Last but not least, we also checked how fast Windows 11 boots from the ADATA Legend 840 SSD. For that, we used BootRacer, which told us that the boot times are fast, about 27 seconds.

How fast Windows 11 boots when using the ADATA Legend 840

The ADATA Legend 840 solid-state drive feels fast in everyday use, offering what we’d call moderate performance for a PCIe 4 SSD, but also significantly better than an average PCIe 3 SSD.

Performance in benchmarks

Next, to get a better picture of how fast the ADATA Legend 840 SSD is, we also ran a couple of benchmarks. The first one was CrystalDiskMark. Using the ADATA Legend 840, we got excellent results in all the tests. The maximum sequential read speed was extremely close to the one advertised by the manufacturer (4963MB/s), while the write speed was actually faster than the one advertised: 4816MB/s vs 4500MB/s! The random speeds were also excellent.

ADATA Legend 840 SSD: CrystalDiskMark benchmark results

PCMark 10’s System Drive Benchmark gave the solid-state drive a score of 2930 points. That’s an excellent score proving once again that the ADATA Legend 840 is a fast SSD.

ADATA Legend 840 benchmark result in PCMark 10

The last benchmark we ran was BlackMagic’s Disk Speed Test. This benchmark is part of a larger software suite for capturing and playing video files. Its results are good indicators of the real-life performance offered by the drive to professionals such as videographers, who work with large files. Our ADATA Legend 840 solid-state drive achieved good read and write speeds, although both were about 600MB/s lower than the advertised maximum speeds.

ADATA Legend 840 SSD: Blackmagic Disk Speed Test benchmark results

The benchmarks we ran show that the ADATA Legend 840 is a capable PCIe 4 solid-state drive. It’s definitely better than PCIe 3 SSDs and a moderately fast one in the world of PCI Express 4 drives.

Bundled software

For the Legend 840 solid-state drive, ADATA offers an app called ADATA SSD ToolBox that looks good and works well. With it, you can check the health of your SSD drive, view information about it and optimize the drive, update its firmware, and erase the data on it in a secure manner.


We like the fact that ADATA offers an SSD health and monitoring app with the Legend 840. It’s useful for keeping tabs on your drive and also comes in handy for keeping its firmware updated.

Will you buy an ADATA Legend 840 SSD?

As you’ve seen, the ADATA Legend 840 is a good PCIe 4 solid-state drive, and its price is reasonable. Do you intend to buy one? Are you still looking at PCIe 3 SSDs? Let us know in the comments section below.

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