System Tray icon used to change display settings, change the clock rate and memory speed for nVidia based graphics cards. This is unnecessary since you can easily configure these settings the way you want them in the Display Properties and not have to mess with them again. Also disable the "NVIDIA Driver Helper Service" if enabled as it can cause this entry to be re-enabled on re-boot (note that this service can also cause extreme shutdown delays if enabled - see here)

System Tray icon used to manage settings for nVidia based graphics cards. May be required for some 3D applications to recognize your card correctly - such as the game "Everquest". Otherwise, settings can be changed manually via Display Properties