xiaomi redmi note 3 memory optimization

http://forum.xda-developers.com/redmi-note-3/how-to/guide-redmi-note-3-sd-mtk-multi-tasking-t3358433


To enable Developer Options Settings App > About Phone > MIUI Version > Keep on tapping till it is enabled.

Settings App > Additional Settings > Battery & Performance > Manage Apps Battery Usage > Power Saving Modes 
Off : All background data & location access of apps will be enabled, All app notifications, less battery life
Standard : Default Setting, good battery life.
Advanced : All background data & location access of apps will be disabled, No app notifications, best battery life

Alternatively you can configure Power Saving Modes for individual apps Settings App > Additional Settings > Battery & Performance > Manage Apps Battery Usage > Choose apps > Select your App > Custom From there you can configure your background data & location services for each app.

Settings App > Additional Settings > Developer Options
Don't Keep Activities : Disabled
Background Process Limit : Standard Limit
Memory Optimization : Disabled
Show All ANRs : Disabled
Force-Closed Apps : Disabled
Turn On MIUI Optimization : Disabled

Security App > Settings > Cleaner Settings > Permissions > Permission Manager : Enabled
Security App > Settings > Clean at lock screen : Never
Security App > Settings > Cleaner Settings > Additional Settings > Memory Clean Up : Disabled
Security App > Permissions > Autostart : Disable unnecessary apps

After doing the changes, restart your device. You might have to re-apply these changes after every MIUI OTA update. These settings have hardly any effect on the battery life. I am getting the same battery backup after using these settings.

You can lock your desired / most frequently used apps in the memory.
Open your app, let the app get launched fully. Now open the recent apps menu. Instead of swiping up to close the app, swipe down the app icon or screen. A lock icon will be displayed on the top right corner of the app icon or screen. This locks the app into the memory & wont get force killed in the background.