Game Booster will scan your system and suggest processes and services that can be safely shut down to free up resources and RAM - all the processes it marks as unnecessary for gaming mode will have check boxes beside them, in case you want to keep a process running. You can also have it look at all running processes and services, and pick and choose the ones you do or do not want to shut down. Make you choices and hit the Switch to Gaming Mode button.It will minimize to your tray, and cannot be shut down until you return to Normal Mode by restoring everything.As far as deciding which processes to have Game Booster shut down, I've been Googling the process names I'm unfamiliar with to find out exactly what they do, and configuring accordingly.

Thats not quite true, GameBooster has no scanning logic what so ever, it compares the preset .ini list of Service Names that are safe to disable in a vanilla install of xp, vista and windows 7, using windows service controller API.

Personally I uncheck Application Experience and Program Compatibility Assistant Service, because these are part of the App compatibility & performance Hotfixes for Windows 7, and support app blocking of apps that don't work at all with windows 7.