parts-quick 16GB Memory for Synology DiskStation DS1621+, DS1621xs+ Compatible DDR4-2666 ECC Unbuffered SODIMM RAM (Equivalent to Synology D4ECSO-2666-16G) at Amazon.com
Synology: Which RAM to Buy For DS1621xs+ NAS – Marius Hosting
32GB & 64GB Unofficial Memory Guide for the Synology DS1621xs+ NAS – NAS Compares
A-Tech 16 GB RAM Ersatz für Synology D4ECSO-2666-16G & D4ES01-16G | DDR4 2666 MHz PC4-21300 SODIMM ECC ungepufferter Speicher kompatibel für NAS & NVR Server: Amazon.de: Computer & Zubehör
NAS Compares - Synology DS1621xs+ NAS – Should You Buy It? | SynoForum.com - The Unofficial Synology Forum
OWC 8GB DDR4 RAM Compatible with Synology DiskStation DS1621+ and DS1621xs+ NAS System 2666MHz PC4-21300 CL19 ECC SODIMM 2Rx8 1.2V Memory Upgrade at Amazon.com
Synology NAS DS1621xs+ Hardware-Installationsanleitung
32GB & 64GB Unofficial Memory Guide for the Synology DS1621xs+ NAS – NAS Compares