Here's my experience with the prologue to chapter 1 transition.
You grab the tentacles for the jump,
cue cutscene (skip or play, usually skip now)
cue the loading screen and the game seems to try to load the chapter one location, play ANOTHER cutscene, and autosave at the same time. This is the problem that just bogs things down for me.
It really should go,
cue the cut SCENES plural as one big cutscene. Don't split them up.
then load chapter 1 location
no saves until after chapter 1 is loaded and the player moves under the nautiloid remnant arch.
