Recently, I purchased a Synology DS1823xs+ and immediately decided to maximize its RAM memory because I run several docker containers and Virtual Machines for testing purposes. According to the official specs, this unit and its AMD Ryzen V1780B CPU support only a maximum of 32GB RAM — a limitation shared with the Synology DS923+, equipped with the somewhat slower AMD Ryzen R1600 CPU, which also allows only 32GB of 2400Mhz RAM. Both CPUs operate with dual-channel memory configurations.

However, I came across several instances on the internet and Reddit pages where individuals were successful in upgrading these units to a whopping 64GB RAM. This spurred me to delve deeper into the RAM specifications and eventually place an order on Amazon.

Synology’s original modules are crazy expensive: $200 for an 8GB (D4ES02-8G) and $400 for a 16GB (D4ES01-16G), offering even lower bandwidth memory. This is despite the CPU’s ability to support a higher memory bandwidth — up to 3200Mhz DDR4, while the native Synology modules are limited to 2666Mhz.

So, I bought two of these: Kingston Server Premier 32GB 3200MHz DDR4 ECC CL22 SODIMM 2Rx8 (based on Hynix chips) modules.
If they are not available, you can also buy these: Kingston Server Premier 32GB 3200Mhz DDR4 ECC CL22 SODIMM 2Rx8 (based on Micron chips).
To my delight, not only did they fit;), but they also worked perfectly! Post-reboot, my Synology reported a system memory of 64GB, utilizing all the free memory as cache. These modules support ECC, have a 3200MHz speed, dual rank (2Rx8), and a cache latency of 22

As a bonus, I sold the original Synology 8GB (D4ES02-8G) module on eBay, making the upgrade even more economical :)