[Note 7 Guides, News, & Discussion] BarryH_GEG:
It's not RAM used that's affecting battery, it's apps kept alive in RAM that are consuming resources (EG: accessing the mother ship, querying the state of the system, archiving user activity, etc.) while they're in the background. That's why the Facebook app takes so much flack because even though it's not alive it's constantly accessing and consuming resources. You and I clearly agree there's supposed to be a direct correlation between an app's state and the amount of resources it consumes. Equally clearly that's not the case in practice. And not just from garage-built questionable apps but from some big names also. That's the reason I believe Samsung and OnePlus have taken the positions they have.

The latest AVG Android App Performance Report saw Snapchat dethrone previous top-spot holders, Facebook and Spotify, thanks to its simultaneous use of your device’s camera, Wi-Fi, mobile data and GPS functionality. Also climbing to the top of the report is the social and blogging platform Tumblr, which has emerged as the highest, traffic-consuming app for the period. Despite the relatively low-level content viewed on the platform – primarily news, short video clips, blogs and some pictures – Tumblr used more data than Netflix and Spotify combined.

There is a costly quest for updates: Topping the list of hidden, battery-draining services this quarter is the innocuously named “com.sec.android.fwupgrade,” which is responsible for delivering periodic Samsung updates to Android devices via Wi-Fi. As with the similarly update-heavy Samsung Security Policy Update (KNOX) and Google Play apps, the service has a massive impact on the battery life of your device

Your browser ‘hoards’ data: Google Chrome emerged as the second-highest storage-consuming app this quarter thanks to its collection of user browsing data over time, joining more obvious apps, such as Spotify and Amazon Kindle

Facebook ‘mis’-manages: A consistent ‘top’ performer in our charts, Facebook has a new contender, this quarter, with its monitoring app, Facebook Pages Manager. The app stores a lot of local content as it tracks page statistics, followers and comments while on the move

Though many users make a conscious choice to download and run high-impact apps on their smartphones, AVG’s research has found a host of apps which silently drain smartphone resources in the background without the users’ knowledge or action. These apps are differentiated in the report as those that run at start-up, versus those that are run by the user. The following apps consumed the most, overall battery drain, storage usage and mobile data combined.​

http://now.avg.com/is-your-app-etite-too-big-for-your-phone/​

If anyone's bored here's how memory management is supposed to by design standard work in Android.

Multitasking the Android Way by Google Software Engineer Dianne Hackborn

http://android-developers.blogspot.com/2010/04/multitasking-android-way.html

Process Stats: Understanding How Your App Uses RAM also by Dianne

http://android-developers.blogspot.com/2014/01/process-stats-understanding-how-your.html

Dianne's commented in discussions like this on XDA before, I'll see if she's willing to pop-in.