Over 600GB free on my main drive. What I did notice is that when you change the settings you have to kind of restart the game fully, changing them willy nilly can cause some performance issues. I had tried running with ray tracing a bit, and it was working fine in the lighthouse but as soon as I got to the forest performance dipped to the 20s and no setting change got performance back up, almost like if the same image is in view the old settings don't get purged.
So could be the settings not clearing properly when changing them (lot of Nixxes "live settings changes" give this issue for me), could be that the ray tracing is hogging memory when changing scenes (but some people are having the issue with non-ray tracing GPUs)
Been playing till the crossing/village portion without a hitch and good performance now, set the game to exclusive full screen as well, not sure if that helped, disabled DRS as it wasn't doing anything. Will see how long this lasts