My friend said clean master can make your phone faster.. did anyone install it for this reason?? Thoughts?
Due to how Android handles memory, you're unlikely to get any answers to the specific question you asked, and the ones you do get will be misinformed. The question you should be asking is if this, or programs like it, actually do make the phone faster. In a word, no. Android is not like Windows when it comes to memory.
In Android, apps sitting dormant in memory don't consume any additional battery or CPU power than if that memory was free. Hence the phrase free memory is wasted memory. The OS is designed to keep the memory full as possible by not killing apps completely, and even initializing some of your common ones in the background. This allows for better multitasking and app switching due to simply leaving apps in memory and not having to restart them from scratch all the time.
App killers, memory boosters, performance enhancers, etc all claim wiping memory will speed up the phone. With current versions of Android, that's simply not true (with the exception of rogue app, which should be handled manually anyway). It's actually the opposite. What will happen is the app kills other apps which uses resources to process. Then the OS restarts those, or other apps to fill the memory again, which takes even more resources. The memory booster app kills again and the progress repeats over and over. So in reality, those kinds of apps reduce performance and increase battery usage. Remember, those dormant apps don't consume any additional battery or CPU in the first place.
Android has its own app management system to handle killing apps to make room for new ones as needed. On a proper functioning system, it works pretty well. There are cases where a bad app could cause problems, but that's not something a memory manager can fix. You need to find the app causing problems and see if force stopping fixes it, or it may require updating/uninstalling if the problem persists. Otherwise, don't bother trying to outsmart the OS when it comes to memory management.