Western Digital WD_BLACK SN770 500GB

The Western Digital WD_BLACK SN770 500GB uses a vertically integrated, proprietary architecture with an in-house SanDisk controller paired with BiCS5 112-layer 3D TLC NAND. It is a DRAM-less design that relies on Host Memory Buffer (HMB) technology to use a portion of system RAM for logical-to-physical mapping tables. The drive prioritizes high-burst throughput and random I/O responsiveness via Western Digital's nCache 4.0 pseudo-SLC caching algorithm to maximize PCIe 4.0 saturation in typical consumer workloads. The controller efficiency lets the SN770 outperform many previous-generation PCIe 3.0 drives in game loading, and the single-sided PCB remains thermally efficient under normal airflow. Large-file transfers that exceed the SLC cache will see write speeds fall to native TLC rates, but recovery from that state is rapid during idle periods.

Key Specifications

• Interface: PCIe 4.0 x4 / NVMe 1.4
• Sequential Read/Write: 5000 MB/s / 4000 MB/s
• Controller: Proprietary SanDisk (DRAM-less)
• NAND Type: Kioxia/WD BiCS5 112-Layer TLC
• Architecture Features: Host Memory Buffer (HMB) enabled
• Physical Layout: Single-sided M.2 2280
• Software Support: WD Dashboard (Game Mode 2.0 supported)

Hardware Alternatives

• Samsung 990 EVO: A direct competitor utilizing a similar DRAM-less, vertically integrated strategy targeting similar thermal and power efficiency profiles.
• Silicon Power UD90 500GB / TeamGroup MP44L: These drives utilize the Phison E21T controller, which serves as the primary third-party alternative to WD’s proprietary controller in the DRAM-less Gen4 segment.
• Lexar NM790: Utilizes the Maxio MAP1602 controller; while often achieving higher peak throughputs, it shares the same underlying HMB-reliant architectural philosophy.