Lessons that I have learned in this game.
There are 3 variables, CPU , System board , RAM.
For modern hardware, we would be extremely lucky for all 3 variables arrive at the lowest cost at the exact same time.
What I learn is to up stock up supply each item when price is low while the other items such as system board or RAM price is high.
In 2016 DDR4 RAM price was cheap ($50 for 16gb stick ) , I purchased whole bunch DDR4 ram. v3 CPU and system board price were high.
Then, late 2016 to 2017 , v3 CPU were onsale, I purchased over 30 E5 v3 CPU with average price around $110-$120
6 months ago, cheap E5 v3 CPU supply dried up , then the X99 and C612 system board became cheap.
I.e. $75-$125 for X99 board, $175-$225 for dual Supermicro , ASUS boards.
Today, my stock of DDR4 ram is very low, so I install a single 4gb DDR4 ram into the v3 CPU system.
In the meantime, I use it for crypto mining to make some money.
Patiently , waiting for cheaper price DDR4 ram to return.