Clean master is a app which promises to clean the r for you, improving the performance and thus increasing the battery too.
The concept is good but is not executed properly.
Its function is to kill the apps running in the background and thus making ram available for faster processing and longer battery life .
But the bad part is that it doesn’t actually provide that . Yes, it does close the apps in the background but they again get restarted and the cycles continue to go on. This lead to decrease battery lifetime . It can simply related as it takes fuel to start a car or any vehicle .the apps too take battery Whitley restarting.
Other than this, the clean master itself takes the ram and also regularly suggesting new apps for download .
So, overall it is just a junk app taking your ram and memory.