If you've noticed that your device becomes too slow, use the [Auto-start Manager] app to check the running apps and their memory use. If you don't need these apps at the moment, you can disable or deny them to release more memory.
There are two scenarios to release the app's memory:
Scenario 1: If the app is currently running and its auto-start setting is set to Allow, slide to Deny to release the memory.
Scenario 2:If the app is currently running and its auto-start setting is set to Deny, move the slider to Allow then move it back to Deny to release the memory. Note: In this scenario, Auto-start Manager also displays memory use of apps even though the app is set to Deny.
You can check the overall memory usage after releasing the memory used by the apps via clicking information icon.