NEMIX RAM 512GB (16x32GB) DDR4 2666 CL19 ECC RDIMM Synology SA6400 memory upgrade

Synology SA6400 512GB kit

This kit provides 512GB of DDR4 2666 ECC registered memory in sixteen 32GB modules for the Synology SA6400 NAS. It targets administrators who need the maximum supported capacity for virtualisation workloads or large file caches. The registered design and ECC function are required by the platform. Systems that accept only unbuffered memory cannot use these modules.

DDR4 2666 registered limits

The memory runs at 2666 MT/s with a CAS latency of 19 at 1.2V. Registered DIMMs add one clock cycle of buffering, which stabilises heavy loads but prevents use in consumer boards that expect unbuffered modules. The 2Rx4 organisation fits the SA6400 memory controller; other rank configurations may not initialise. Mixing with slower or faster DDR4 kits will force the system to the lowest common speed.

288-pin RDIMM practicalities

Each module is a standard 288-pin DDR4 RDIMM without a heat spreader, so clearance inside the SA6400 chassis is not affected by tall heatsinks. The 16-module count fills every available slot, leaving no room for future expansion without removing existing sticks. Installation follows the vendor slot-order guide; incorrect population order can prevent the NAS from posting.