Although Android Lollipop was designed to be fluid and friendly for customers to use, it contains some powerful features including some detailed screens that allow you to check how much RAM individual applications - both system and third party - are using. In stock Lollipop, the memory manager screens are kept in Settings, then Apps and from here, swipe across to see the running applications. However, in the Android M Preview, the same screen is somewhat more hidden. Again, head to Settings, then Apps, but next head to the menu button at the top right of the screen. From here, open Advanced, then Memory. From here and as you'll see in the gallery at the bottom of the screen, there are a range of options and information screens allowing you to dive reasonably deep into the operating system to gain an appreciation of what is going on under the skin.
Android M gives users the ability to check the current, maximum and average RAM use of applications. The screens use a dark green color to show the average RAM usage and light green illustrates the maximum RAM used by any one particular application. The same screen shows how frequently a particular application is running, as some run constantly and some somewhat less often! Tapping on an application also shows the running processes along with each process RAM usage and some applications give you the opportunity to stop them: doing this produces the familiar "Force Stop" warning button that hasn't much changed for a long time now!
What is the utility of the RAM management screens? Android has an elegant, sophisticated and generally robust RAM and application process manager and whilst it can sometimes go awry, it tends to maintain and look after the device well enough such that most users don't feel the need to check up on what's using application RAM. However, it can be interesting to take a look and see how much memory individual applications use and to identify those that have a habit of using a lot of memory, which could cause slowdowns in the device. Now of course, it is important to remember that just because the RAM manager is present in the preview of Android M, this does not mean that it will also be present in the final release of the software: it may be removed or revised in a subsequent preview.