The purpose of my thesis to analyze Android memory usage, CPU usage and effects of task killers on memory and CPU. I had great research about memory allocation and reclaiming. General idea is that Android devices should use task killer to improve performance and battery life. I could understand with the help of my thesis, this is not true. After my extended research work, I have concluded that contrariwise, task killer applications decrease performance because of cleaning memory. This document clearly explains what is going on with the device when the user use task killer and how the system works with suspended applications.