[rpierce99]

What arrrghhh is trying to say here is that the amount of free RAM available to the system is not what makes a system fast or slow. When you see "sluggishness" at a certain amount of free ram, that is because something didn't have enough free RAM to do what it needed to do, so it either sent some RAM to swap so that it could have free RAM, used some swap space for itself which is slower, or killed an app that was taking some RAM. All of those activities take processor/IO time. Getting more FREE RAM is like buying a bigger mailbox because the amount of mail you get is taking more than 75% of the available mail box space. Who cares if you only have 25% of your total mailbox space free? Until you exceed 100% you don't notice issues with your mail delivery service. Free RAM is wasted money, linux uses as much RAM as you tell it that it can have to store things for faster opening the next time. That's why that app lets you pick that threshold for how much free RAM you want to keep, if you are always opening a new app (maybe you like the free app of the day) or opening large photos, you'd want to have enough free ram to do those activities without swapping. Someone who opens the same 3 apps every day, never opens pictures or downloads anything new doesn't need to have as much free RAM, so they can adjust it up the other way to keep their 3 apps in memory at all times.

TL;DR: Linux will be greedy, if you tell it that it can have all but 20MB, it will take all but 20MB to give you better performance, try to ignore your free RAM count except to get it to match the way you use your phone.