D4ES04-4G Synology 4GB DDR4 Ram Module – ECC Unbuffered SODIMM

D4ES04-4G Overview

The Synology D4ES04-4G is a specialized 4GB DDR4 memory module specifically designed to expand the capacity and enhance the stability of Synology DiskStation and Rack Station NAS servers. Operating at 2666MHz (PC4-21300), this 260-pin SO-DIMM is optimized for high-performance data management in professional and small-business environments. As an ECC Unbuffered (ECC UDIMM) module, it provides a critical layer of data protection by detecting and correcting single-bit memory errors—essential for maintaining the integrity of stored files and preventing system crashes during 24/7 operation. Running at a power-efficient 1.2V, it is tailored for the specific hardware architectures of the 21-series through 25-series models (such as the DS925+, DS1821+, and RS1221+). This genuine Synology upgrade ensures full manufacturer compatibility and unlocks the reliable throughput required for intensive NAS workloads like virtualization, backup synchronization, and media streaming.