I have a voip app that has a serious performance issues when it runs on the background. Does running it as a service make any difference?
Making an app run as a service helps in avoiding shutdown by the Android OS? More information on this would be helpful.
Yes, if you run it as a foreground service then it will almost never be killed (unless there are really no other way for Android to free memory) and it will be treated as a running app, so there should be no performance issue.
You can get more details about foreground services in the documentation.