It seems that just when you think you figured something out, they come along and change everything on you and you've gotta learn it all over again.
There are so many types of memory modules out there, and if you don't put in the right one, your computer gets very unhappy very quickly.
I always try to check the MB manual to find out what types the board will support.
Some sellers used to have a "Memory Configurator" that you plugged in the make and model of your 'puter and it told you what you needed to buy. I haven't seen one of them in a long time.
Probably don't have 'em anymore 'cause so many people "roll their own".
I did like the website with the different descriptions and so-on.
DaGeek