The WD Blue SN500 is an entry-level NVMe solid-state drive (SSD) manufactured by Western Digital. Announced in March 2019, it was the first NVMe offering in the WD Blue product line, which had previously consisted exclusively of SATA-based SSDs. It is positioned as a budget-conscious solution that delivers NVMe performance at near-SATA pricing, targeting mainstream users, system builders, and resellers seeking to upgrade from traditional SATA storage.
As an entry-level NVMe SSD, the WD Blue SN500 bridges the gap between Western Digital’s SATA-based WD Blue SSDs and their high-performance WD Black NVMe lineup. The drive was marketed as delivering up to three times the performance of high-end SATA SSDs, and positioned the SN500 to compete against other budget NVMe offerings such as the Toshiba/OCZ RC100. At launch, the drive was priced at approximately $54 for the 250GB model and $76 for the 500GB variant, a 10-15% premium over comparable SATA SSDs at the time.
Technical Specifications
| WD Blue SN550 | 250GB Model | 500GB Model |
|---|---|---|
| Model Number | WDS250G1B0C | WDS500G1B0C |
| Formatted Capacity | 250GB | 500GB |
| DRAM | N/A | N/A |
| Interface | PCIe Gen3 x2 | PCIe Gen3 x2 |
| Sequential Read (MB/s) | 1,700 | 1,700 |
| Sequential Write (MB/s) | 1,300 | 1,450 |
| Random Read 4K IOPS | 210K | 275K |
| Random Write 4K IOPS | 170K | 300K |
| Endurance (TBW) | 150 | 300 |
| NAND Type | 64-layer BiCS3 3D TLC - 533 MT/s | 64-layer BiCS3 3D TLC - 533 MT/s |
| Controller | Triton MP28 | Triton MP28 |
| SLC Cache Size | ~3GB | ~6GB (estimated) |
| Average Active Power | 75mW | 75mW |
| Peak Power | 1.8A | 1.8A |
| Low Power (PS3) | 25mW | 25mW |
| Sleep Power (PS4) | 2.5mW | 2.5mW |
| Warranty | 5 years | 5 years |
Controller
The SN500 uses a proprietary Western Digital/SanDisk in-house controller (labeled 20-82-007010 on the 500GB model), which represents an earier, scaled-down version of the architecture used in the WD Black SN750. This controller supports the NVMe 1.3 specification and communicates with the host system via a PCIe Gen3 x2 interface, limiting theoretical bandwidth to 2GB/s in each direction. Unlike the four-lane configuration found in higher-end NVMe drives, this two-lane design was chosen to reduce costs while still providing substantial performance improvements over SATA.
The controller features a unique DRAM-less design but incorporates a small amount of embedded SRAM within the controller package itself. Western Digital’s research indicated that with optimized data locality algorithms, they could maintain 90-99% of the performance of a traditional DRAM-equipped SSD with as little as 4MB of embedded memory, compared to the typical 512MB external DRAM chip found on comparable drives. Notably, the controller does not utilize the NVMe Host Memory Buffer (HMB) feature, distinguishing it from other DRAM-less designs that rely on system memory.
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.
NAND Type & Specifications
Western Digital and its subsidiary SanDisk manufactures NAND in a joint venture with Kioxia (formerly Toshiba Memory). The SN500 uses 3rd-generation 64-layer BiCS 3D TLC (triple-level cell) NAND flash memory. It is packaged in a single-chip config (labeled 05561-512G on the 500GB model), which simplifies the design and reduces costs. Compared to earlier, planar NAND, BiCS3 offers improved density and reliability while maintaining competitive performance characteristics. In this SSD, the NAND operates at 533 MT/s over a 4-channel controller configuration.
Power Consumption
The WD Blue SN500 offers excellent power efficiency, with specifications indicating:
- Average active power: 75mW
- Peak power (10μs): 1.8A
- Low power state (PS3): 25mW
- Sleep state (PS4): 2.5mW
In real-world testing, the drive typically operates between 1-2W under load, with power consumption rarely exceeding 2.5W even under sustained workloads. The active idle power consumption is approximately 1W, though the drive’s ability to enter deeper sleep states can be platform-dependent. This low power draw makes the SN500 suitable for mobile applications (i.e. laptops) where battery life is a priority.
Reviews
The WD Blue SN500 defies expectations… Both the high-end WD Black and mainstream WD Blue SSD product lines are now using controllers based on their own controller architecture, and both instantiations of that architecture seem to be very successful for a first-generation release.
The WD Blue SN500 NVMe SSD shown here offers up to 1.7GB/s reads, with 1.45GB/s writes… it still spanks anything based on the legacy SATA interface.
WD makes the claim that the WD Blue SN500 NVMe makes an impressive performance jump of three times that of the high-end SATA SSDs.
With a price of only $73 for the reviewed 500 GB version, it’s one of the most affordable drives on the market that still delivers very decent performance. We saw no thermal-throttling, even when fully loaded and completely uncooled.
A value NVMe proposition that is capable of rattling some cages… The new SN500 SSD allows you to purchase NVMe storage in the 20 cents per GB region.
Was this helpful?
1 / 0