ADATA Legend 840 512GB PCIe 4.0 NVMe SSD Specifications (2026)
ADATA Legend 840 512GB uses an Innogrit IG5220 controller with 3D TLC NAND and Host Memory Buffer technology for PCIe Gen4 reads up to 5,000 MB/s and writes of 4,500 MB/s.
Controller & Memory
The ADATA Legend 840 512GB occupies the mid-range tier of PCIe 4.0 x4 NVMe storage, using the Innogrit IG5220 Rainier Pro controller with 3D TLC NAND flash memory. Sequential read speeds reach 5,000 MB/s with writes up to 4,500 MB/s, placing it between entry-level Gen4 drives and the flagship 7,000+ MB/s tier powered by controllers like the Phison E18.
The IG5220 is a DRAMless design that relies on Host Memory Buffer (HMB) technology, which borrows a small portion of system memory for the NAND mapping table. This approach reduces component cost while maintaining acceptable performance for everyday desktop and gaming workloads. The Legend 840 also supports SLC caching to accelerate write performance during burst operations.
ADATA positions the Legend 840 as a budget-friendly Gen4 option for gamers and general users who want faster-than-SATA performance without paying flagship prices. The 512GB capacity provides a practical amount of storage for operating systems, applications, and a selection of modern games.
The drive uses the standard M.2 2280 form factor and generates moderate heat during operation. The IG5220 controller is more power-efficient than flagship Gen4 controllers, making the Legend 840 suitable for laptops and compact builds where thermal headroom is limited.
Storage Comparisons:
Legend 840 Performance & Benchmarks
The 512GB Legend 840 delivers 5,000 MB/s sequential read and 4,500 MB/s write throughput over PCIe 4.0 x4. While these speeds fall short of the 7,400 MB/s ceiling offered by flagship Gen4 drives, they represent a significant improvement over SATA SSDs limited to around 550 MB/s and provide adequate bandwidth for most consumer workloads.
ADATA Legend 840 512 GB vs M.2 4.0 x 4 peers
Switch between sequential throughput and random IOPS to see how this drive stacks up against other M.2 4.0 x 4 SSDs in our database. The highlighted bar is the drive on this page — click any other bar to open that drive.
- Patriot Viper PV593 1 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV593 2 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV593 4 TB: 14,500 MB/s read, 14,000 MB/s write
- Patriot Viper PV573 2 TB: 14,000 MB/s read, 12,000 MB/s write
- ADATA Legend 840 512 GB (this drive): 5,000 MB/s read, 4,500 MB/s write
Random 4K performance is where the HMB DRAMless design shows its limitations compared to DRAM-equipped alternatives. Under light desktop and gaming loads the drive feels responsive, booting systems quickly and launching applications without noticeable delay. Under sustained mixed workloads the absence of dedicated DRAM can cause occasional latency spikes as the drive manages the NAND mapping table through the HMB mechanism.
The dynamic SLC cache handles burst write operations well for typical consumer use. During prolonged file transfers exceeding the cache capacity, write speeds drop to the native TLC pace. The 512GB capacity provides a reasonably sized cache pool for most everyday transfer scenarios.
Thermal output from the IG5220 controller is moderate, typically running cooler than flagship Gen4 drives. This makes the Legend 840 a good fit for laptops, Mini-ITX builds, and motherboards without M.2 heatsink coverage. Most users will not need to add aftermarket cooling.
ADATA Legend 840 vs Competitors
See how the Legend 840 stacks up against other M.2 4.0 x 4 drives in our database:
Compare with rival drives:
Endurance, TBW & Warranty
ADATA provides a five-year limited warranty on the Legend 840 series from the date of original purchase. TBW endurance ratings for the Legend 840 scale with capacity, with the 512GB model carrying an endurance rating consistent with other mid-range Gen4 drives in this class. ADATA global support network handles warranty claims through authorized retailers and regional service centers. For warranty service, proof of purchase from an authorized ADATA distributor is required. The five-year warranty term reflects ADATA confidence in the reliability of the Innogrit IG5220 controller platform and the 3D TLC NAND flash under normal consumer operating conditions. Keep your purchase receipt in a safe place, as ADATA requires proof of purchase date to process any warranty claims.
ADATA Legend 840 512 GB Specifications
| Category | Value |
|---|---|
| Capacity [?] | 512 GB |
| Interface [?] | M.2 4.0 x 4 |
| Controller [?] | Innogrit IG5220 |
| Memory type [?] | 3D TLC |
| DRAM [?] | HMB (no DRAM) |
| Read speed (MB/s) [?] | 5000 |
| Write speed (MB/s) [?] | 4500 |
| Read IOPS [?] | 650000 |
| Write IOPS [?] | 600000 |
| Endurance (TBW) [?] | 650 |
| MTBF (million hours) [?] | 1500000 |
| Warranty (years) [?] | 5 |
Verdict: Is the Legend 840 Worth It in 2026?
The ADATA Legend 840 512GB delivers solid mid-range PCIe 4.0 performance at a budget-friendly price point. The Innogrit IG5220 controller with 3D TLC NAND flash provides 5,000 MB/s reads and 4,500 MB/s writes, which is more than adequate for gaming, general desktop use, and light content creation.
The DRAMless HMB design keeps costs down while maintaining acceptable everyday performance. Thermal requirements are modest, making the Legend 840 versatile across desktop and laptop platforms. If you want Gen4 storage without paying flagship prices, the Legend 840 512GB is a sensible choice from a well-established memory products manufacturer. The drive offers a practical balance of speed, capacity, and affordability for most PC users.
+ Pros
- 5,000 MB/s reads deliver solid mid-range Gen4 performance
- 3D TLC NAND for better endurance than QLC alternatives
- HMB technology maintains performance without dedicated DRAM
- Moderate thermal output suitable for laptops and compact builds
- Five-year limited warranty from ADATA
- Cons
- DRAMless design limits sustained random performance
- Speeds well below the 7,400 MB/s Gen4 flagship ceiling
- SLC cache exhaustion during prolonged large file transfers
- Occasional latency spikes under mixed heavy workloads
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