SanDisk WD Blue SN5100

Launched in August 2025, the WD Blue SN5100 is an entry-level M.2 NVMe solid-state drive (SSD) developed by SanDisk (formerly Western Digital's SSD division). It is the successor to the WD Blue SN5000 and the first WD Blue NVMe drive released after Western Digital and SanDisk parted ways, with the latter taking over all NAND-based products going forward. With QLC NAND flash memory and PCIe Gen 4.0 interface the SN5100 is positioned as a budget-to-mainstream solution for cost-conscious system builders and consumers.

Key competitors include the Crucial P310, Kingston NV3 (both QLC based), and TLC-based entry-level offerings such as the Samsung 990 EVO. Against more recent TLC-based alternatives like the Crucial T500, Samsung 990 EVO Plus, and its sibling WD Black SN7100, the SN5100 offers lower pricing while sacrificing some sustained write performance and endurance. However, reviewers have noted that the performance gap between this QLC drive and TLC alternatives has narrowed considerably, making it viable for most consumer workloads.

Technical Specifications

Official datasheet

Controller

The SN5100 uses SanDisk's proprietary Polaris 3 controller (model A101-000172-A1 or A101-000103-A1), a four-channel DRAM-less design that relies on Host Memory Buffer (HMB) technology. The controller can access up to 64MB of system memory for mapping tables as substitute for an on-board DRAM cache. This same controller architecture is also utilized in the higher-end WD Black SN7100, demonstrating scalability across different market segments.

Cache: DRAM-less

SanDisk's nCache 4.0 technology, introduced in 2023 with the SN580 and SN770, is a hybrid pseudo-SLC (single-level cell) caching system. This technology features both static and dynamic cache portions: the static cache resides outside user space and handles smaller random writes with higher endurance, while the dynamic cache varies in size based on available drive capacity. Data is initially written to fast SLC blocks before being transferred to slower QLC blocks during idle periods, with folding operations completing at approximately 400 MB/s.

Power Consumption

The drive demonstrates efficient power management with average read/write power consumption ranging from 3.8W (500GB) to 4.3W (4TB). In idle sleep mode, power consumption drops to just 4-4.5mW, making it suitable for laptop deployment where battery life is important.

Performance Characteristics

The SN5100 delivers sequential read speeds up to 7,100 MB/s and sequential write speeds up to 6,700 MB/s (on 1TB and 2TB models), which is an improvement of around 30% over its predecessor. Random performance reaches up to 1 million IOPS for reads and 1.3 million IOPS for writes on select capacities.