QNAP TS-453D comes with only 4GB of RAM, and if you are going to do RAM intensive tasks like using Containers or Virtual Machines, you will definitely need to upgrade the RAM.
I bought the Crucial 8GB DDR4 2666 MT/s (PC4-21300) SODIMM 260-Pin Memory (CT8G4SFRA266) from Amazon.sg during Black Friday as they are having a sale. I got it for S$31.08 with free shipping to Singapore as my total order is over S$60 and I am an Amazon.sg Prime member.
Synology DDR4 RAM has been available in the market for a few years now and it is mainly targeted at businesses.
But with the release of the Synology DiskStation DS20 Plus series for consumers, you can finally get the DDR4 RAM to go along with your new shiny DS920+, DS720+, DS420+, or DS220+.
Benjamin recommended me to go with AMD instead of Intel. So I will be getting the AMD Ryzen R-3700X.
For RAM, Benjamin recommended the G.Skill Trident Z Neo Series 32GB. It is a PC4-28800, 3,600 MHz, 288 pins RAM with a CAS Latency of CL16 (16-19-19-39) at 1.35V.
Not many people realized this, but Synology has their own brand of RAM.
Officially, Synology always recommends you to use their brand of RAM for 100% compatibility and reliability. It comes with three years warranty and is made in Taiwan.