So I kept getting lag from sorting, which I do a lot, and I went through the options and narrowed it down to the "Server Item Movement" option. Beforehand it would freeze for a couple seconds every time I sorted. Afterwards there was absolutely no lag.

Same thing is happening to me repeatedly, but no one else on the server has this issue. I do not have server item movement turned on, could it be related to a specific java version? I did change versions without luck. Can't figure out why I'm the only person experiencing this.

All that option changes is how clicks are sent to the server, they do (nearly) the same thing either way.

If anything having it on should be about the same speed -- there's some extra packet processing needed for the 'on' position, but the movement attempt does less extra processing when it's on.