Mobs Are ( Still ) Not Moving

My laptop can run games without glitching or lagging. However, mobs can only move a small bit before freezing, on all my singleplayer worlds this is happening. It's much like lag.

EDIT: Through the in-game day, the sun will move, jump back, move, jump back etc. the day is still progressing but glitching.

Items are also taking a while to pick up, and usually, have to leave them to disappear