OWC 8GB DDR4 2666 ECC SODIMM for Synology DS1525+ DS1825+ DS1825xs+ DS725+ DS925+

NAS memory upgrade

This 8GB DDR4 ECC SODIMM is built for Synology DiskStation models DS1525+, DS1825+, DS1825xs+, DS725+ and DS925+. It adds capacity to NAS appliances that handle file serving, virtualization or container workloads where data integrity matters. The module replaces Synology part numbers D4ES01-8G and D4ES02-8G with a single 260-pin stick. Buyers needing higher-density DIMMs or registered memory for other platforms should look elsewhere.

Sustained workload behaviour

Rated at 2666 MT/s with CL19 timing, the module runs at JEDEC-standard PC4-21300 speeds without overclocking. ECC circuitry corrects single-bit errors on the fly during long backup, scrubbing or database jobs. The 1Rx8 organisation keeps electrical loading low when multiple slots are populated. Systems that require faster data rates or lower latency than the rated specification will not gain from this part.

Thermals, noise and power

Operating at 1.2 V without a heat spreader, the module draws minimal power inside a sealed NAS chassis. Passive cooling from system airflow is sufficient for continuous operation. Zero moving parts means the upgrade adds no audible noise. Builders targeting ultra-low-power envelopes or fanless enclosures will find the thermal profile compatible.