Western Digital’s WD Blue SN570 is a consumer-grade NVMe solid-state drive (SSD) manufactured by Western Digital. Announced on October 4, 2021, it is the successor to the WD Blue SN550 in the company’s Blue product line. The PCIe 3.0 x4 M.2 drive targets budget-conscious consumers and mainstream computing applications. As part of the WD Blue lineup, it’s positioned between the entry-level WD Green series and the performance-oriented WD Black line. The SSD competes directly with other DRAM-less offerings such as the Samsung 980 (non-Pro) and Crucial P3.
Technical Specifications
| Specification | 250GB | 500GB | 1TB | 2TB |
|---|---|---|---|---|
| Model Number | WDS250G3B0C | WDS500G3B0C | WDS100T3B0C | WDS200T3B0C |
| Interface | PCIe 3.0 x4, NVMe 1.4 | PCIe 3.0 x4, NVMe 1.4 | PCIe 3.0 x4, NVMe 1.4 | PCIe 3.0 x4, NVMe 1.4 |
| Form Factor | M.2 2280 | M.2 2280 | M.2 2280 | M.2 2280 |
| NAND Type | BiCS5 112-layer 3D TLC | BiCS5 112-layer 3D TLC | BiCS5 112-layer 3D TLC | BiCS5 112-layer 3D TLC |
| Sequential Read (MB/s) | 3,300 | 3,500 | 3,500 | 3,500 |
| Sequential Write (MB/s) | 1,200 | 2,300 | 3,000 | 3,500 |
| Random Read 4KB IOPS | 190K | 360K | 460K | 600K |
| Random Write 4KB IOPS | 210K | 390K | 450K | 600K |
| Endurance (TBW) | 150 | 300 | 600 | 900 |
| Average Active Power | 90mW | 90mW | 90mW | 90mW |
| Low Power (PS3) | 30mW | 30mW | 30mW | 30mW |
| Sleep (PS4) | 5mW | 5mW | 5mW | 5mW |
| Max Operating Power | 3.5W | 4.0W | 4.5W | 4.5W |
| Warranty | 5 years | 5 years | 5 years | 5 years |
Controller
The SN570 uses a proprietary SanDisk-designed controller manufactured in-house by Western Digital. It has been identified with various part numbers across different capacities, including 20-82-10023-A1, 20-82-10048-A1, and 20-82-10081-A1 (Polaris MP16+). This four-channel DRAM-less design makes use of NVMe Host Memory Buffer (HMB) technology, which allocates 64MB of system RAM to compensate for the lack of onboard DRAM cache. The controller manages the mapping tables that track data locations on the NAND flash, which is a function handled by dedicated DRAM in higher-end drives.
Cache Architecture
Like other TLC NAND-based NVMe SSDs, the WD Blue SN500 employs a dynamic SLC (single-level cell) write cache to accelerate write transfer rates. In the 250GB model, this cache is limited to approximately 3GB, while the 500GB model features a proportionally larger cache. Once the SLC cache is exhausted, write speeds drop to the native TLC speeds of approximately 432MB/s for the 250GB model and slightly more for the 500GB variant. Despite its small size, Western Digital’s testing showed this cache size was sufficient for typical consumer workload burst patterns in Windows 10 environments.
Like most other modern NVMe SSDs based on TLC or QLC NAND, the WD Blue SN570 implements a pseudo-SLC (single-level cell) caching mechanism to improve write performance. This static cache is relatively small compared to competitors, measuring approximately 12GB on the 1TB model (scaling with capacity). Thanks to the cache, sequential performance is up to 3.5 GB/s read and 3.0 GB/s write for brief bursts. But once the SLC cache is exhausted, write performance reverts back to native TLC speeds of around 500-600 MB/s, comparable to SATA SSD performance.
NAND Type & Specifications
BiCS5 (Bit Cost Scalable Gen 5) 112-layer 3D TLC (triple-level cell) NAND was developed by Kioxia (formerly Toshiba Memory) in cooperation with SanDisk/Western Digital. It’s an upgrade from the 96-layer BiCS4 flash used in the predecessor SN550. The BiCS5 technology features quad-plane architecture for improved parallelism and performance. Western Digital confirmed that the drives will maintain TLC NAND throughout their product lifecycle and will not transition to QLC (Quad-Level Cell) flash – something that sparked controversy with the predecessor.
Power Consumption
Like its predecessors, the WD Blue SN570 is a highly efficient mainstream SSD:
- Average Active Power: 90mW across all capacities
- Low Power State (PS3): 30mW
- Sleep State (PS4): 5mW
- Maximum Operating Power: 3.5W (250GB), 4.0W (500GB), 4.5W (1TB and 2TB)
These figures enable operation without thermal throttling under most common usage scenarios, including sustained write operations.
Reviews
The WD Blue SN570 improves upon its predecessor by boosting performance while retaining rock-bottom pricing and high reliability, making it a solid value pick for most system builders.
The WD Blue SN570 is priced extremely competitively at only $90 for the 1 TB version. While pricing suggests ‘entry-level,’ the drive is actually the second-fastest PCIe 3.0 SSD we ever tested.
WD’s SN570 Blue shows a marked increase in performance over the previous Blue SN550 thanks to the NAND technology it uses and controller updates …
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