The game is loading assets for the new area, not much you can do. More noticeable if your cpu/gpu is older.

What I found works nicely, if you turn up the draw distance to high as possible, even if you turn everything else down; you will get less spikes due to more of the land loaded at once. What causes it for me is the loading of the land when walking around. It's dreadful. 80 FPS -> 20 FPS... seriously pretty bad.

Upgrading your computer to 16GB RAM might help, but honestly, the game stutters in general every now and then regardless (especially at world saves), so don't expect too much.

My wife plays this on a prior gen i5 6600K with a GTX 1050Ti and 16GB RAM, SSD on medium settings and has no major issue with it.