CM Speed Booster is a utility for your mobile that aims to make it run quicker. It does this by cleaning your phone of junk files and freeing up memory so your phone, in theory, can use more of its power for the things you really want to do.
Free space and memory
CM Speed Booster has three main functions. There's Storage Insight, which tells you how much of you storage space is being used, and its condition. Then there is Phone Boost, which frees up RAM by killing unnecessary processes running in the background. Finally Junk Files detects unnecessary files on your device and deletes them for you, giving you more space to store the things you like, such as photos.
With a clean and clear interface, CM Speed Booster is very easy to use, and for the most part it's well explained. The first time you use it, you'll likely free up quite a lot of storage space, which is useful. The memory boost is less clear cut - you will gain more memory by stopping background apps from running, but if you're running a recent version of Android there's little evidence this will improve your phone's performance. If you have an older device that struggles to run smoothly, you may see a temporary improvement.
The main problem with CM Speed Booster is found when you enter each of its functions. Open Storage Insight, for example, and you'll find tabs called Similar Photos and Rarely used apps. You would assume tapping these will give you information about these, or solve a problem. But what actually happens is the Google Play store opens, suggesting you install CM Clean Master. Almost every area of Speed Booster has a button which will take you out of the app to install this. While Clean Master may not be a bad app, being repeatedly shot out of Speed Booster without warning is very annoying.
Disappointing and annoying
If CM Speed Booster stuck to its basic task of cleaning memory and storage space, it would be much improved. But it's riddled with buttons that send you, without warning, to the Play Store to install another app. This kind of behavior is annoying and ruins what could otherwise have been an excellent user experience.