As far as beta went, when I did most of my testing on this, the game reads certain assets from the hard drive once, causing a stutter, and once it's loaded your game would run better. I always advocated using your skills at least once in town prior to going out to hunt. That being said, when it loaded monster assets/spells there wasnt much you could do.
As for rubber banding, if you see yourself repeatedly rubberbanding to the same spot, rather than stuttered rubberbanding (not sure how to describe this) You're usually snagged on some object, such as a rock or chest, and until you "clear it" will remain rubber banding to the spot. For example, you can teleport out, or try walking away from the obstruction in a different direction to become "unstuck"
Im not sure if any of this still is true or adheres, but it may be worth looking at
XI Wiki


