Changing a process's priority to high will only prioritize that process to use more CPU resources or CPU resources first before other processes. This is only a setting to affect computer performance, and has nothing to do with Jagex's detection system.
Or purchase a proxy. OP, you should have really done some searching around and googling before making this topic, in order to figure out what "changing bot's ip address" really entails.
Is there any noticeable difference in how a script ran through the mirror client (behaviorally) interacts with the game, as opposed to the regular client? I have yet to try it. Thanks